Parts of a Triangle: Using angles in a triangle

AB||CD

x = 50

Calculate the size of angle $\alpha$.

67

Look at the triangle below.

Calculate the size of angle $\alpha$.

103

AB || CD

x = 80

Calculate the size of the $\alpha$.

30

AB || CD

Calculate the size of the angle $\alpha$.

43

AB || CD

Calculate the size of angle $\alpha$.

84

Shown below is the triangle ABC.

$∢A$ is 3 times greater than the sum of the rest of the angles.

Calculate $∢A$.

135°

The triangle ABC is right angled.

$∢A=4∢B$

Calculate angles $∢B$ and $∢A$.

72 , 18

ABC is a right triangle.

$∢A=20°$

Is it possible to calculate the size of $∢C$?

If so, what is it?

Yes, 70°.

Given the triangle ABC.

Dado ∢B>90° , $∢A=20°$

Is it possible to calculate a ? $∢B$?

If so, find how much the angle is equal to.

$$

No

ΔABC is a scalene triangle with acute angles.


Which angle is larger,
$∢C$ or $∢A$?

There is no way to know.

The triangle ABC is a right triangle.

Which angle is larger, $∢B$ or $∢A$?

∢A>∢B

ABC is an equilateral triangle.

Which angle is larger, $∢B$ or$∢A$?

$∢A=∢B$

Triangle ABC is an obtuse triangle.

Which angle is larger, $∢B$ or $∢A$?

∢B>∢A

ABC is an isosceles triangle

($∢A$ is the predominant angle).

Which angle is larger,$∢B$ or$∢C$?

$∢C=∢B$

The triangle ABC is isosceles.

$∢C=50°$

Is it possible to calculate the size of angle $∢A$?

If so, then what is it?

Yes, 80°

ABC is an obtuse triangle.

$∢C=\frac{1}{2}∢A$$$

$∢B=3∢A$

Is it possible to calculate $∢A$?

If so, then what is it?

Yes, 40°.

ABC is an isosceles triangle.

DE is parallel to BC.

Angle A is equal to 3X plus 22.

Express the size of angle DEC.

$101+1.5x$