IXL | Triangle Angle-Sum Theorem

The diagram shows a triangle.

32°

40°

What is the value of

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Learn with an example

The diagram shows a triangle.

41°

40°

What is the value of

The sum of the interior angle measures of a triangle is 180°.

First, look at the interior angle measures in the triangle.

Set the sum of the interior angle measures of the triangle equal to 180°. Solve for

41°

40°

180°

81°

Combine like terms

180°

Combine like terms

Subtract 81° from both sides

99°

Subtract 81° from both sides

Divide both sides by 9

11°

Divide both sides by 9

So,

11°

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