Question

The height of a triangle is 2 less than 5 times it's base. If the base of the triangle is x feet, and the area of the triangle is 12 square feet, which equation models the situation

Answer 1

Answer:

Area A = 12 = 1/2 × x × (5x-2)

5x^2 - 2x -24 = 0

Solution;

Base x = 2.4

Height h = 10 ft

Step-by-step explanation:

Given;

base of the triangle is x feet;

Base = x

The height of a triangle is 2 less than 5 times it's base;

Height = 5x - 2

the area of the triangle is 12 square feet;

Area A = 12 ft^2

The area of a triangle is;

Area A = 1/2 × base × height

Substituting the base and height;;

Area A = 1/2 × x × (5x-2)

Area A = 1/2 × (5x^2 - 2x)

Area A = 12

12 = 1/2 × (5x^2 - 2x)

Multiply through by 2.

24 = (5x^2 - 2x)

5x^2 - 2x -24 = 0

Solving the simultaneous equation;

x = 2.4 or -2

Since the base cannot be negative;

x = 2.4 ft

Height h = 5x -2 = 5(2.4) - 2 = 12 - 2 = 10 ft

Base x = 2.4

Height h = 10 ft