Right Obtuse and Acute Angles in Triangles

Bella has a window in her bedroom shaped like a triangle. Each angle of the triangle measures less than 90 degrees. What kind of triangle is her window?

• Straight

• Acute

• Obtuse

• Right

This is a right triangle because —

• it is facing the right way

• it has 3 acute angles

• it has one 90 degree angle

• it does not have one obtuse angle

Stuart drew a triangle. ∠ABC had a measure of 60 degrees. ∠BAC also had a measure of 60 degrees. ∠ACB also had a measure of 60 degrees. What kind of triangle is ΔABC?

• Right

• Acute

• Obtuse

• Straight

Which is a true statement?

• An acute triangle has three acute angles.

• An obtuse triangle has two obtuse angles.

• A right triangle has two right angles.

• A right triangle has 3 congruent angles.

The measure of each angle of an acute triangle must be —

• equal 90°

• less than 90°

• total 360°

• more than 90°

Identify the statements that are true.

• A scalene triangle has exactly two congruent sides.

• An obtuse triangle has exactly one obtuse angle.

• An acute triangle has three acute angles.

• A right triangle has one right angle and at least one obtuse angle.

• An equilateral triangle has three acute angles.

In a ____________ triangle one angle is exactly 90 degrees.

• acute

• right

• obtuse

• 360 degrees

What kind of triangle is this?

• acute

• right

• obtuse

• 360 degrees

What kind of triangle is this?

• acute

• right

• obtuse

• 360 degrees

In an ______________ triangle, all three angles are less than 90 degrees.

• acute

• right

• obtuse

• 360 degrees