SOLUTION: The height of a triangle is 8m more than twice the length of the base. The area of the triangle is 21 m^2. Find the height of the triangle.

Algebra ->  Triangles -> SOLUTION: The height of a triangle is 8m more than twice the length of the base. The area of the triangle is 21 m^2. Find the height of the triangle.      Log On


   

Question 1176988: The height of a triangle is 8m more than twice the length of the base. The area of the triangle is 21 m^2. Find the height of the triangle.
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Area of triangle = 1/2 * base * height
Let length of base be x

21 = 1/2 * x * (2x+8)
42 = x(2x+8)
42 = 2x^2 +8x
2x^2 +8x -42 =0
divide equation by 2
x^2+4x-21=0
(x+7)(x-3)=0
x =-7 or x=3
taking positive value
x=3
base =3
height = 2x+8 = 14 m