Question

The base of a triangle is 7 inches more than 4 times the height. If the area of the triangle is 93 square inches, find the base and height.

Answer 1

Answer:

Step-by-step explanation:

Let the height = h

Let the base = 4h + 7

Area of a triangle = 1/2 * b * h

Area = 93 square inches

1/2 * (4h + 7)* h = 93            Multiply both sides by 2

(4h + 7) * h = 93*2

(4h + 7)*h = 186                    Remove the brackets

4h^2 + 7h = 186                   Subtract 186 from both sides.

4h^2 + 7h - 186 = 0

Use the quadratic formula to solve

a = 4

b = 7

c = - 186

x1 = (-7 + sqrt(7^2 - 4*4*(-186) ) /2*4

x1 = (-7 + sqrt(49 - 16*(-186)) / 8

x1 = (-7 + sqrt(49 + 2976)) / 8

x1 = (-7 + sqrt(3025)) / 8

x1 = (-7 +55 ) / 8

x1 = (48)/8

x1 = 6

There is another root, but it has to be minus and therefore cannot be used as a length. x2 = - 7.75

h = 6

b = 4*6 + 7 = 31

Check

Area = 1/2 * b * h

Area = 1/2 * 31 * 6

Area = 1/2 *186

Area = 93 which is what we were given so the answer is correct.