The height of a triangle is 3 cm less than its base. The area of the triangle is 90 square cm. Find the base of the triangle.

Question

so I think I have the answers BUT it doesn't match 90 square cm. The answers were base: -15, 12. Height: -18, 9. However, it does equals to -90 IF 1/2 x -15 x 12 but it's negative. 😭😭

Answer 1

(b(b - 3))/2 = 90

b² - 3b = 180

b² - 3b - 180 = 0

(b - 15)(b + 12) = 0

b - 15 = 0

b = 15

b + 12 = 0

b = -12

Because we measure using positive numbers, we disregard this "answer."