Exercise 17 Page 852

Let's start by recalling that a hemisphere is a solid that is half of a sphere.

This means that, to find the area of a hemisphere, we should calculate the area of half of a sphere with the same radius and add the area of a great circle. Surface Area of a Hemisphere [0.8em] A=1/2(4π r^2)+π r^2 We first need to calculate the radius. To do so, we will consider the given fact that the circumference C of the great circle is 15π mm. A great circle is the circle that contains the center of the sphere. Because of that its radius is equal to the radius of the hemisphere. Let's recall the formula for the circumference. C=2π r We can substitute 15π for C in this formula and solve for the radius r.

We know that r=7.5mm. We can substitute this value in the formula for the area of a hemisphere and simplify.

The area of the hemisphere to the nearest tenth is 530.1mm^2.