Square root of 100 = 10 cm. Next, 10*2 = 20^2 = 400 ft. Next, convert cm into ft, which would make 100 into about 3.3 ft. The ratio would then be about 3/400. Does that help?
Indirect material cost: y
explained by units produced: x
Linear regression. Cost estimation equation: y=mx+b
Constant: b=$15,640
Standard error of y estimate=$3,600
r^2=0.7704
Number of observations: n=22
x coeffient: m=11.25
Standard error of x coefficient=2.19
m=11.25, b=15,640 → y=11.25x+15,640
Answer: The cost estimation equation is y=11.25x+15,640