Classifying Shapes Triangles Acute Obtuse Right

Look at the shapes.

Which triangles appear to be right triangles?

• 1 and 2

• 1 and 5

• 2 and 5

• 3 and 4

Which statement about the two triangles are correct?

• Both triangles are acute triangles.

• Both triangles are obtuse triangles.

• Triangle 1 is an obtuse triangle, and Triangle 2 is a right triangle.

• Triangle 1 is an obtuse triangle, and Triangle 2 is an acute triangle.

Which shape must always have one pair of perpendicular line segments and at least one right angle?

• acute triangle

• right triangle

• rhombus

• trapezoid

An acute triangle is

• A triangle with 1 obtuse angle

• A triangle with all sides the same length

• A parallelogram

• A triangle with 3 acute angles

Which triangle has all three of its angles measuring less than 90°?

• Acute

• Right

• Obtuse

• Equilateral

Which triangles are acute triangles?

• 
• 
• 
• 

I know this is an acute triangle because

• there is a 90° angle

• all of the angles are less than 90 degrees

• there is an angle greater than 90° but less than 180°

An Acute Triangle has all acute angles.

• True

• False

An Acute Triangle has all acute angles.

• True

• False

• Isosceles Triangle

• Equilateral Triangle

• Right Triangle

• Scalene Triangle