Math
posted by Gilda on .
Application of Quadratic Equations
The base of a triangle is longer than twice its corresponding height by 1 cm. The area of the triangle is 105 cm(square). Find the height of the triangle

height  x
base  2x + 1
(1/2)(base)(height) = area
(1/2)(2x+1)(x) = 105
x(2x+1) = 210
2x^2 + x  210 = 0
(x10)(2x+21) = 0
x = 10 or x = 21/2 , but obviously x has to be positive, so
x = 10
The height is 10 cm
check:
height is 10
base is 21
area = (1/2)(21)(10) = 105
answer is correct