Triangles

Look at the sides of this triangle. What type of triangle is this?

• Scalene

• Isosceles

• Equilateral

• Right-Angle

In a ____________ triangle one angle is exactly 90 degrees.

• Scalene

• Isosceles

• Equilateral

• Right-Angle

If a triangle has three equal sides and three equal angles, what type of triangle is it?

• Scalene

• Isosceles

• Equilateral

• Right-Angle

The Triangle Sum Theorem states that the sum of all angles in a triangle is ______

• 45°

• 90°

• 180°

• 360°

In a triangle △PQR, PT bisects ∠QPR. Prove that PQ is greater than QT. Click on 'Yes' when it is completed.

• Yes

• No

Answer explanation

Since PT bisects ∠QPR, we have, ∠QPT = ∠TPR .......(1) Also, in △PTR, ∠PTQ > ∠TPR.... [As an exterior angle of a triangle is always greater than either of the interior opposite angles] Therefore, ∠PTQ > ∠QPT.....(from (1)) Since in a triangle, the greater angle has the greater side opposite to it, ∴ PQ > QT Hence, proved.

Find the measure of the missing angle.

• 10°

• 50°

• 90°

• 140°

Find the measure of the missing angle.

• 40°

• 60°

• 90°

• 140°

The exterior angle of a triangle is equal to...

• 180°

• The sum of the two opposite interior angles

• 90°

• The sum of any two interior angles

Find the measure of the missing angle.

• 40°

• 60°

• 90°

• 120°

Find the measure of the missing angle.

• 55°

• 75°

• 105°

• 120°