It's hard to read your image, unfortunately. Seems to me that it states that C=50.2 and that the formula for circumference is C=2pi*r.

50.2

In that case, C= 50.2 = 2(3.14)r, and r = ------------- = 7.99.

6.28

We are to round this to one decimal place. That results in r = 8.0.

The below solved example problem may be useful to understand how the values are being used in the mathematical formulas to find the triangle area. Find the area of a triangle having the base b = 18 & height h = 12 cm?

It takes Franklin 14 hours to make a 200-square-foot cement patio thus his rate is 1/14 patios per hour

It takes Scott 10 hours to make the same size patio thus his rate is 1/10 patios per hour

let x = the hours they need to make the patio together

the together rate is 1/x patios per hour

now we have

1/14 + 1/10 = 1/x ( equation )

by solving we find:

x = 35/6 hr

x = 5 5/6 hr

x = 5 hr (5/6)*60 min

x = 5 hr 50 min

<span>Franklin and Scott will need 5 hours and 50 minutes to make the patio together.</span>