Rectangle with an area of 16 sq. in.
Height is 4 inches less than base
What is the measure of the base?
.
Area = Height * Base
16 = (B-4) * B
B^2 - 4B - 16 = 0
B = (4 +- sqrt(16 - 4(1)(-16)) )/2
B = (4 +- sqrt(16 + 64) )/2
B = (4 +- sqrt(80) ) /2
B = (4 +- 4sqrt(5) ) /2
B = 2 +- 2sqrt(5)
It's a physical measurement so the +- is just a +
B = 2 + 2sqrt(5) inches