Find the area to this problem

254.34 in²

Step-by-step explanation:

Given:

Diameter of the circle = 18 in

To find:

Area of the circle

Solution:

Let the area be a.

First, we find the radius of the circle by dividing the diameter by 2.

This comes out to be 9 in.

Now, we apply the formula

Solving, we get

a = 3.14 × (9)²

a = 3.14 × 81

a = 254.34 in²

Hope this helps! :D

C)He should also take a sample from each of the other history classes in all of the other grades in the middle school.

Step-by-step explanation:

Not only students in the 8th grade are in the middle school, there are other students in other grades who are in the middle school and are enrolled in history classes. Leo's sample is only from one grade of the middle school. In fact, including Ms. Lopez's and Mrs. Frank's classes in the selection of sample is not sufficient. Leo has to take a sample from the remaining grades to avoid making a wrong conclusion as a result of bias in the choice of data.