Syed S. answered 11/24/19
Cornell Alum with 6+ years of tutoring experience
Set the height dimension of the triangle as h and your base dimension b becomes b=2+2h because the base is "two feet longer than twice the height."
Knowing that the area is 140 sqft and that the area of a triangle= bh/2 you can set up and solve your equation as such:
Area = bh/2
140= bh/2
140=((2+2h)h)/2
280=(2+2h)h
280= 2h+2h^2
2h^2+2h-280=0
Using the quadratic formula:
h= (-2 +- sqrt(4 - 4*2*-280))/(2*2)
h= 11.3427 or − 12.3427 <-- IGNORE negative h value bc you're working with dimensions
Because b=2+2h, b= 24.6854
So, height is 11.3427 ft and base is 24.6854 ft.
As a check, plug into the area formula and you'll see that bh/2 = 140 sqft!