Answer:
The height of the triangle is 8 cm
Step-by-step explanation:
First we need to write down the question in a mathematical format and then solve.
let b be the base of the triangle and h be the height of the triangle
"The base of a right triangle is 13 less than 2 times the height" can be written as
b = 2h - 13 -----------------------------------------------------(1)
"The area of the triangle is 12 square cm" can be written as;
area of the triangle = 12 cm²
but area of a triangle = ×b × h
This implies that
×b × h = 12 cm²
bh = 24 cm² --------------------------------------------------(2)
substitute equation (1) in equation (2)
(2h - 13)h = 24
2h² - 13h = 24
2h² - 13h - 24 = 0 ----------------------------------------------(3)
The above is now a quadratic equation, so we will solve by completing the square method.
Find two numbers such that its product will give -48 and its sum will give -13
The two numbers are -16 and 3
Replace -13h by (-16h + 3h) in equation (3)
2h² - 13h - 24 = 0
2h² - 16h + 3h - 24 = 0
2h(h - 8) + 3(h-8) = 0
(h-8)(2h+3) = 0
either h-8 = 0
h = 8
OR
2h + 3 = 0
2h = -3
h =-3/8
There is no such thing as negative length, therefore h= 8 is the answer
The height of the triangle is 8 cm