Parts of a Triangle Practice Problems & Worksheets

Master triangle terminology with interactive practice on heights, medians, angle bisectors, and perpendicular bisectors. Build geometry skills step-by-step.

📚What You'll Master in Triangle Parts Practice
  • Identify and draw triangle heights from vertices to opposite sides
  • Locate medians that divide triangle sides into equal segments
  • Construct angle bisectors that create equal angles at vertices
  • Draw perpendicular bisectors from midpoints of triangle sides
  • Find midsegments connecting midpoints of two triangle sides
  • Distinguish between different types of triangle lines and their properties

Understanding Parts of a Triangle

Complete explanation with examples

Terms used in triangle calculations

  • Line

A line is a general term for straight lines (hence its name) that extend from a specific point on the triangle.

  • Height

Height is a line that extends from a specific vertex and reaches perpendicularly to the opposite side, creating a right angle. The height is marked with the letter h (from the word height).

  • Median

The median is also a line extending from a specific vertex to the opposite side, but it reaches exactly the middle of the opposite side and divides it into two equal parts.

  • Angle Bisector

An angle bisector is a line that extends from a specific vertex and actually divides the vertex into two equal angles.

  • Perpendicular Bisector

A perpendicular bisector is a line that extends from the middle of a side perpendicular to it.

  • Midsegment

A midsegment is a line that connects the midpoints of two sides and is parallel to the third side, with its length being half of it.

  • Opposite Side

An opposite side is the side that is located opposite to a specific vertex and does not pass through it.

Diagram of a triangle ABC illustrating key geometric concepts: height (H) in green, median in blue, angle bisector in red, perpendicular bisector from CB in orange, midsegment in purple, and the side opposite to vertex A highlighted in orange. Labels are color-coded for clarity.

Detailed explanation

Practice Parts of a Triangle

Test your knowledge with 33 quizzes

Look at the triangle ABC below.

Which of the following lines is the median of the triangle?

AAABBBCCCDDDEEE

Examples with solutions for Parts of a Triangle

Step-by-step solutions included
Exercise #1

What is the median of triangle ABC?

AAABBBDDDCCCEEEFFF

Step-by-Step Solution

To determine the median of triangle ABC, we must identify a segment connecting a vertex of the triangle to the midpoint of the opposite side.

Examining the diagram, point F appears to be located on side AC. Given the configuration, point F divides side AC into two equal segments, which makes F the midpoint of AC.

Therefore, segment CF connects vertex C to the midpoint F of side AC. This characteristic aligns with the definition of a median in a triangle.

Hence, the median of triangle ABC is CF CF .

Answer:

CF

Exercise #2

Look at triangle ABC below.

Which is the median?

αααAAABBBCCCDDDEEE

Step-by-Step Solution

To solve this problem, we must identify which line segment in triangle ABC is the median.

First, review the definition: a median in a triangle connects a vertex to the midpoint of the opposite side. Now, in triangle ABC:

  • Point A represents the vertex.
  • Point E lies on line segment AB.
  • Line segment EC needs to be checked to see if it connects vertex E to point C.

From the diagram, it appears that E is indeed the midpoint of side AB. Thus, line segment EC connects vertex C to this midpoint.

This fits the definition of a median, verifying that EC is the median line segment in triangle ABC.

Therefore, the solution to the problem is: EC \text{EC} .

Answer:

EC

Exercise #3

In an isosceles triangle, the angle between ? and ? is the "base angle".

Step-by-Step Solution

An isosceles triangle is one that has at least two sides of equal length. The angles opposite these two sides are known as the "base angles."
The side that is not equal to the other two is referred to as the "base" of the triangle. Thus, the "base angles" are the angles between each of the sides that are equal in length and the base.
Therefore, when we specify the angle in terms of its location or position, it is the angle between a "side" and the "base." This leads to the conclusion that the angle between the side and the base is the "base angle."

Therefore, the correct choice is Side, base.

Answer:

Side, base.

Exercise #4

Look at the two triangles below.

AAABBBCCCDDDEEEFFF

Is AD a side of one of the triangles?

Step-by-Step Solution

The task is to determine if the segment AD AD is a side of any of the given triangles. Based on the diagram, we have two distinct triangles:

  • ABC\triangle ABC: Formed by the points A,B,C A, B, C .
  • DEF\triangle DEF: Formed by the points D,E,F D, E, F .

For ABC\triangle ABC, the sides are AB,BC, AB, BC, and CA CA .

For DEF\triangle DEF, the sides are DE,EF, DE, EF, and FD FD .

In analyzing both triangles, we observe that:

  • The side AD AD is not listed as one of the sides of either triangle.

Thus, the conclusion is clear: AD is not a side of either triangle.

Therefore, the answer is No.

Answer:

No

Exercise #5

Look at the two triangles below. Is DE a side of one of the triangles?

AAABBBCCCDDDEEEFFF

Step-by-Step Solution

To solve whether the segment DE DE is a side of one of the triangles, we must identify the sides of each triangle in the given diagram.

The first triangle is labeled ABC \triangle ABC :

  • Vertices are A,B, A, B, and C C .
  • Sides by this configuration are AB,BC, AB, BC, and AC AC .

The second triangle is labeled DEF \triangle DEF :

  • Vertices are D,E, D, E, and F F .
  • Sides formed are DE,EF, DE, EF, and DF DF .

Upon inspection, we see that DE DE is listed as a side of DEF \triangle DEF , confirming that it indeed is one side of this triangle.

Therefore, the conclusion is:

Yes, DE DE is a side of one of the triangles.

Answer:

Yes

Frequently Asked Questions

What is the difference between a height and a median in a triangle?

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A height (altitude) is a line from a vertex perpendicular to the opposite side, forming a 90° angle. A median is a line from a vertex to the midpoint of the opposite side, dividing that side into two equal parts. The height focuses on perpendicularity, while the median focuses on bisecting the opposite side.

How do you identify the opposite side of a triangle vertex?

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The opposite side is the side that doesn't touch the vertex you're looking at. For example, in triangle ABC, the opposite side to vertex A is side BC. The opposite side is always across from the vertex, never connected to it.

What makes an angle bisector different from other triangle lines?

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An angle bisector divides an angle at a vertex into two equal smaller angles. Unlike heights or medians that go to the opposite side, angle bisectors focus on splitting the angle itself. If angle A is 60°, its angle bisector creates two 30° angles.

How long is a midsegment compared to the third side of a triangle?

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A midsegment is always exactly half the length of the third side (the side it's parallel to). This is the Triangle Midsegment Theorem. For example, if the third side is 10 units long, the midsegment will be 5 units long.

Where does a perpendicular bisector start in a triangle?

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A perpendicular bisector starts from the midpoint of any triangle side and extends perpendicular (at 90°) to that side. It doesn't originate from a vertex like heights, medians, or angle bisectors do. Instead, it bisects the side itself.

Can a triangle have multiple heights, medians, and angle bisectors?

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Yes! Every triangle has exactly three of each: three heights (one from each vertex), three medians (one from each vertex), and three angle bisectors (one for each angle). Each serves a different geometric purpose in triangle analysis.

What tools do I need to draw triangle parts accurately?

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You'll need: 1) A ruler for measuring and drawing straight lines, 2) A protractor for measuring angles and creating perpendicular lines, 3) A compass for finding midpoints and creating equal segments. These tools help ensure your triangle constructions are precise.

Why are triangle parts important in geometry problems?

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Triangle parts help solve area calculations, prove congruence, find missing measurements, and understand triangle properties. Heights are used in area formulas, medians help locate centroids, and angle bisectors are crucial for angle relationships and triangle similarity problems.

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