Question

The path of a rotating lawnmower blade has a diameter of 24 inches and a circumference of about 75 inches. On a smaller model of the lawnmower, the blade has a circumference of about 12.5 inches. What is the diameter of the model?

1. pick a proportion

2. substitute the given values

3. find the factor

4. solve for the missing part

(please solve and tell me each question/number and tell me it like 1.(answer) 2.(answer) and so on and so on)

Answer 1

1. diameter over the circumference = diameter over the circumference
d/C = d/C
2. substitute the given values
d/C = d/C
24/75 = d/12.5
3. find the factor
24/75 can be simplified down to 8/25
8/25 = d/12.5
4. solve for the missing part
8/25 = d/12.5
cross multiply
(8*12.5) = 25d
100 = 25 d
divide both sides by 25 to isolate d
4 = d
The diameter of the model is 4 inches.

Hope this helps :)