Answer:
(b) Circle C is shown. Line segment A C is a radius with length 7 centimeters.
Step-by-step explanation:
Given
![Minimum\ Area = 135cm^2](https://tex.z-dn.net/?f=Minimum%5C%20Area%20%3D%20135cm%5E2)
![Maximum\ Area = 155cm^2](https://tex.z-dn.net/?f=Maximum%5C%20Area%20%3D%20155cm%5E2)
![\pi = 3.14](https://tex.z-dn.net/?f=%5Cpi%20%3D%203.14)
Required
Which circle could she use
To do this, we simply calculate the areas of all the given circles
The area of a circle is:
![Area = \pi r^2](https://tex.z-dn.net/?f=Area%20%3D%20%5Cpi%20r%5E2)
Where
![r = radius](https://tex.z-dn.net/?f=r%20%3D%20radius)
![a.\ r = 6cm](https://tex.z-dn.net/?f=a.%5C%20r%20%3D%206cm)
The area is calculated as thus:
![Area = \pi r^2](https://tex.z-dn.net/?f=Area%20%3D%20%5Cpi%20r%5E2)
![Area = 3.14 * (6cm)^2](https://tex.z-dn.net/?f=Area%20%3D%203.14%20%2A%20%286cm%29%5E2)
![Area = 3.14 * 36cm^2](https://tex.z-dn.net/?f=Area%20%3D%203.14%20%2A%2036cm%5E2)
![Area = 114.04cm^2](https://tex.z-dn.net/?f=Area%20%3D%20114.04cm%5E2)
![b.\ r = 7cm](https://tex.z-dn.net/?f=b.%5C%20r%20%3D%207cm)
The area is calculated as thus:
![Area = \pi r^2](https://tex.z-dn.net/?f=Area%20%3D%20%5Cpi%20r%5E2)
![Area = 3.14 * (7cm)^2](https://tex.z-dn.net/?f=Area%20%3D%203.14%20%2A%20%287cm%29%5E2)
![Area = 3.14 * 49cm^2](https://tex.z-dn.net/?f=Area%20%3D%203.14%20%2A%2049cm%5E2)
![Area = 153.86cm^2](https://tex.z-dn.net/?f=Area%20%3D%20153.86cm%5E2)
<em></em>
![c.\ r = 8cm](https://tex.z-dn.net/?f=c.%5C%20r%20%3D%208cm)
The area is calculated as thus:
![Area = \pi r^2](https://tex.z-dn.net/?f=Area%20%3D%20%5Cpi%20r%5E2)
![Area = 3.14 * (8cm)^2](https://tex.z-dn.net/?f=Area%20%3D%203.14%20%2A%20%288cm%29%5E2)
![Area = 3.14 * 64cm^2](https://tex.z-dn.net/?f=Area%20%3D%203.14%20%2A%2064cm%5E2)
![Area = 200.96cm^2](https://tex.z-dn.net/?f=Area%20%3D%20200.96cm%5E2)
![d.\ r = 9cm](https://tex.z-dn.net/?f=d.%5C%20r%20%3D%209cm)
The area is calculated as thus:
![Area = \pi r^2](https://tex.z-dn.net/?f=Area%20%3D%20%5Cpi%20r%5E2)
![Area = 3.14 * (9cm)^2](https://tex.z-dn.net/?f=Area%20%3D%203.14%20%2A%20%289cm%29%5E2)
![Area = 3.14 * 81cm^2](https://tex.z-dn.net/?f=Area%20%3D%203.14%20%2A%2081cm%5E2)
![Area = 254.34cm^2](https://tex.z-dn.net/?f=Area%20%3D%20254.34cm%5E2)
<em>From the calculations above; only the circle in option (b) has an area within the required range of 135 to 155cm^2</em>