IXL | Find missing angles in special triangles

A right triangle has one angle that measures 10°. What is the measure of the other acute angle?

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question

A right triangle has one angle that measures 50°. What is the measure of the other acute angle?

key idea

The measures of the angles of a triangle add up to 180°.

solution

A right triangle has a 90° angle, so you know that two of the angles are 90° and 50°.

Find the missing angle. Set the sum of the angle measures equal to 180° and solve.

90° + 50° + n

180°

Add

140° + n

180°

Add

Subtract 140° from both sides

180° − 140°

Subtract 140° from both sides

Simplify

40°

Simplify

So, the other acute angle measures 40°.

Looking for more? Try these:

Lesson: Types of triangles

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Lesson: Types of triangles

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