Question

What is the area of a circle with a diameter of 40 cm? use 3.14 for pi

Answer 1

Answer:

1256 cm

Step-by-step explanation:

1. Write the equation to find the area of the circle.

The area of a circle is equal to r^2 (radius squared) multiplied by pi, which in this case we use 3.14. So the equation in numbers is basically r^2*3.14.

2. Find the radius.

Since all we have right now is the diameter of 40 cm, we have to convert the diameter into radius. To do that, we have to just divide the diameter by 2! 40/2=20. The equation says to square the radius (which means to multiply the number by itself). 20^2=400 or you could just say 20*20=400, because they both mean the same thing!

(Just so you know, the diameter is halfway across the circle, and the radius is halfway of the diameter, so that's why you divide by two!)

3. Finish off by multiplying pi!

In the equation it says to multiply pi, in this case 3.14, by 400 because that's what we got when we found the radius. 400*3.14=1256. And finally, you got the answer!

Sorry if this explanation took forever but I hope this helped :D