Question

The height of a triangle is 8ft greater than the base. The area of the triangle is 136.5 square ft. Find the length of the base and the height of the triangle

Answer 1

Answer:

the base is 9/2 ft and the height is 9/2 + 8, or 25/8, ft.

Step-by-step explanation:

Note that the formula for the area of a triangle is A = (1/2)(base)(height).  Let's abbreviate that to A = (1/2)(b)(h).   We are told that h = b + 8.

Then A = 136.5 = (1/2)(b)(b + 8), or

               (after multiplying both sides by 2)

          A = 273 = b^2 + 8b

                which, when put into standard quadratic form, becomes:

b^2 + 8b - 273 = 0

The coefficients of this quadratic are a = 1, b = 8 and c = -273.

Thus, the discriminant is b^2 - 4ac, or 64 - 4(1)(-273) = 1156 = 17^2.

The roots are then

      -8 ± √1156            -8 ± 17

x = --------------------  =  ------------ = 9/2 and -25/2

              2                          2

Only the root 9/2 makes sense here, because measurements of length are positive.

Thus, the base is 9/2 ft and the height is 9/2 + 8, or 25/8, ft.