Find the measure of each marked angle. In Exercises 19–22, m and n are parallel.
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Fill in the blank(s) to correctly complete each sentence.

The sum of the measures of the angles of any triangle is ________________ .

Fill in the blank(s) to correctly complete each sentence.

An isosceles right triangle has one ________________ angle and ______________ equal sides.

Fill in the blank(s) to correctly complete each sentence.

An equilateral triangle has _________________ equal sides.

Find the measure of each marked angle. In Exercises 19–22, m and n are parallel. See Examples 1 and 2 .

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Classify the triangle below according to its sides and angles.

I. Equilateral

II. Isosceles

III. Scalene

IV. Acute

V. Obtuse

VI. Right

Find the missing angle $\theta$ for this right triangle.

Calculate the missing side of the triangle below.

Calculate the missing side of the triangle below.