Question

In an isosceles trapezoid, the longest base is 11", a leg is 5", and the height is 4".

Find the length of the shorter base of the trapezoid.

Answer 1

The non-parallel sides of an isosceles
trapezoid are equal and form congruent rt triangles when the altitude is drawn. The base of the rt tiangles can be calculated:

X^2 + Y^2 = Z^2,
X^2 + 4^2 = 5^2,
X^2 + 16 = 25,
X^2 = 25 - 16,
X^2 = 9,
X = 3.

2X + B2 = B1,
2*3 + B2 = 11,
6 + B2 = 11,
B2 = 11 - 6,
B2 = 5.