Answer:
Let us assume base of the window = b feet.
Height is 3 feet less than base, that is = (b-3).
Given area of the triangle = 20 feet square.
We know formula for area of a triangle:
Area = \frac{1}{2}21 × Base × Height
Plugging values in formula, we get
20 = \frac{1}{2} b \times (b-3)21b×(b−3)
\mathrm{Multiply\:both\:sides\:by\:}2Multiplybothsidesby2
40=b\left(b-3\right)40=b(b−3)
40=b^2-3b40=b2−3b
b^2-3b-40=0b2−3b−40=0
Factoring quadratic, we get
\left(b+5\right)\left(b-8\right)(b+5)(b−8) =0
b+5=0
b=-5
b-8=0
b=8.
For base we can take only positive value.
Therefore, base of the triangle = 8 feet and height = 8 -3 = 5 feet.
