Question

A circle centered at the origin passes through the point (3, 5). What is the area of the circle to the nearest tenth of a square unit?

34.0 units2
106.8 units2
213.5 units2
None of the above

Answer 1

A = π(34), or approx. 106.8 units²

Explanation:

Recall that the formula for the area of a circle is A = πr².

If (3, 5) is a point on the circle at hand, then the radius (found using the Pythagorean Theorem) is r = √(3² + 5²) = √(9 + 25) = √34.

Then r² = 34, and the area of this circle is

A = π(34), or approx. 106.8 units²