Triangle ABC: Finding AB Length When AD=6, CE=3, and CB=5

Question

Given the triangle ABC

AD=6 CE=3 CB=5

What should be the length of AB so that the area of a triangle ABC is compatible with the rest of the data in the drawing?

555666333AAABBBCCCDDDEEE

Video Solution

Solution Steps

00:00 Find the length of AB so that the triangle areas match
00:03 We'll examine the size of sides and lines according to the given data
00:12 Perpendicular according to the given data
00:17 AD is also the height in the triangle
00:20 We'll use the formula for calculating triangle area
00:25 (height multiplied by base) divided by 2
00:38 We'll substitute appropriate values and solve for the area
00:51 This is the triangle area
01:01 Let's calculate the triangle area using height and other side
01:07 We'll substitute appropriate values and solve for AB
01:27 Multiply by denominator to eliminate the fraction
01:32 Isolate AB
01:42 Simplify as much as possible
01:48 And this is the solution to the problem

Step-by-Step Solution

Given that AD is perpendicular to CB

We can establish that AD is the height of the triangle ADB

Hence the formula for the area of triangle ABC=

AD×CB2 \frac{AD\times CB}{2}

We insert the existing data into the formula:

6×52=302=15 \frac{6\times5}{2}=\frac{30}{2}=15

Due to the fact that CE is also a height, we can calculate the area of triangle ABC as follows:

CE×AB2 \frac{CE\times AB}{2}

Since we found the area of triangle ABC, we will insert the data into the formula:

15=3×AB2 15=\frac{3\times AB}{2}

We then multiply across:

30=3AB 30=3AB

Lastly we divide both sides by 3:

303=3AB3 \frac{30}{3}=\frac{3AB}{3}

AB=10 AB=10

Answer

10 cm