Triangles

Classify the triangle: A triangle with exactly two sides of equal length.

• Scalene triangle

• Equilateral triangle

• Right-angled triangle

• Isosceles triangle

Which would be the best classification for the triangle shown?

• acute isosceles
• right scalene
• acute scalene
• obtuse scalene

Which triangle has one angle that is exactly 90 degrees?

• Acute triangle

• Obtuse triangle

• Right triangle

• Isosceles triangle

Answer explanation

The triangle that has one angle that is exactly 90 degrees is called a Right triangle.

Name this triangle by its sides.

• scalene

• isosceles

• equilateral

• obtuse

The lengths of a triangle are given below. Is the the triangle obtuse, acute, or right?

5, 5, 12

• right

• obtuse

• acute

• Not a triangle

What type of triangle is shown?

• acute

• obtuse

• right

Classify the triangle. 

• acute isosceles

• obtuse isosceles

• obtuse scalene

• obtuse equilateral

Name this triangle by its angles and sides.

• obtuse, isosceles

• acute isosceles

• right, scalene

• acute, equilateral

A triangle has angles measuring 45 degrees, 45 degrees and 90 degrees. The triangle has two congruent sides.

• scalene acute
• equilateral acute
• isosceles right
• scalene right

This is . . .

• a scalene triangle

• an obtuse triangle

• an equilateral triangle

• a right triangle