Math Flashcards

A triangle has angles measuring 45°, 55°, and x°. What is x?

Answer: 80

The angles of a triangle sum to 180°, so x = 180 - 45 - 55 = 80.

The area of a circle with radius 5 is closest to:

Answer: 78.5

Area = πr² = π(25) ≈ 78.54.

In a right triangle, the two legs measure 9 and 12. What is the hypotenuse?

Answer: 15

By the Pythagorean theorem, c = √(81 + 144) = √225 = 15.

Two parallel lines are cut by a transversal. If one co-interior (same-side interior) angle is 110°, the other is:

Answer: 70°

Co-interior angles are supplementary, so the other angle = 180° - 110° = 70°.

A rectangle has a perimeter of 36 and a length of 10. What is its width?

Answer: 6

P = 2(l + w), so 36 = 2(10 + w), giving w = 8. Wait — 2(10+w)=36 → 10+w=18 → w=8. Answer is 8.

The volume of a cylinder with radius 3 and height 4 is:

Answer: 36π

V = πr²h = π(9)(4) = 36π.

An isosceles triangle has a vertex angle of 40°. What are the measures of its base angles?

Answer: 70° each

The two base angles are equal and sum with 40° to 180°, so each = (180 - 40)/2 = 70°.