Posted by ben on .
Suppose an isosceles triangle has perimeter 10 cm. Find an expression for its area A as a function of the
length of its base b (assume that the other two sides are the sides of equal length). What is the domain
of A?

Math 
Reiny,
let each of the equal sides be x
so 2x + b = 10
x = (10b)/2
let the height be h
h^2 + (b/2)^2 = [(10b)/2]^2
h^2 + b^2/4 = (100  20b + b^2)/4
h^2 = (10020b+b^2b^2)/4
h^2= (10020b)/4
h = √(10020b)/2
area = (1/2)bh
= (1/2)b(√(10020b)/2
= (1/4) b√(10020b)
check my arithmetic