Bluebook SAT Test Lines, Angles, and Triangles 7

Question 1

In a triangle, angle A = 90° and angle B = 38°. What is angle C?

Accepted Answer

52°

Answer

Angle C = 180° − 90° − 38° = 52°.

Question 2

Which angle pair is always congruent when two parallel lines are cut by a transversal?

Accepted Answer

Alternate interior angles

Answer

Alternate interior angles formed by a transversal and parallel lines are always equal.

Question 3

Isosceles triangle RST has RS = RT and vertex angle R = 100°. What is each base angle?

Accepted Answer

40°

Answer

Each base angle = (180° − 100°) ÷ 2 = 40°.

Question 4

Parallel lines are cut by a transversal. The angle at the top-left is 115°. What is the co-interior angle at the bottom-right?

Accepted Answer

65°

Answer

Co-interior angles are supplementary: 180° − 115° = 65°.

Question 5

In similar triangles PQR and STU, angle P = 55° and angle Q = 75°. What is angle U?

Accepted Answer

50°

Answer

Angle R = 180° − 55° − 75° = 50°; U corresponds to R, so angle U = 50°.

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