M3.Triangles & Circles

Front

What is the formula for the area of a circle?

Back

A = πr², where A is the area and r is the radius.

Front

What is the circumference of a circle?

Back

The circumference is the distance around the circle, calculated as C = πd or C = 2πr.

Front

What does the term 'area' refer to in geometry?

Back

Area refers to the amount of space inside a two-dimensional shape, measured in square units.

Front

What does the term 'circumference' refer to?

Back

Circumference refers to the distance around a circle.

Front

How do you find the diameter of a circle if you know the circumference?

Back

Use the formula d = C/π, where d is the diameter and C is the circumference.

Front

If a circle has a radius of 2 inches, what is its area?

Back

A = π(2)² = 4π in².

Front

If a circle has a circumference of 31.4 inches, what is its radius?

Back

r = C/(2π) = 31.4/(2π) = 5 inches.

Front

What is the sum of the angles in a triangle?

Back

The sum of the angles in a triangle is always 180 degrees.

Front

If one angle in a triangle is 90 degrees and another is 50 degrees, what is the measure of the third angle?

Back

The third angle is 40 degrees (180 - 90 - 50 = 40).

Front

What is an acute angle?

Back

An acute angle is an angle that measures less than 90 degrees.