algebra and trigonometry
posted by raven .
find the dimensions of a rectangle having perimeter 14m and diagonal of length 5m

Let the diagonal be c and the sides a and b
b = sqrt (c^2  a^2) = sqrt(25a^2)
Perimeter = 2a + 2b = 2a + 2sqrt (25a^2) = 14
14  2a = 2 sqrt (25a^2)
196  56a + 4a^2 = 4(25a^2) = 100 4a^2
8a^2 56a +96 = 0
a^2 7a + 12 = 0
(a3)(a4) = 0
The side lengths are 3 and 4