Gems

A trapezoid has parallel sides 13 and 21 cm long. The longer of the two nonparallel sides is 17 cm and the shorter is perpendicular to a parallel side. What is the area of the trapezoid?

In triangle ABC, measure of angle A is 30 degrees. AC=4, AB=3 square root of 3. Find BC.

The sides of a triangle are 15, 20 and 28. How long are the segments into which the bisector of the largest angle separates the opposite side

Triangle ABC has a right angle at C. The bisector of an exterior angle at B intersects line AC at D. If AB=13 and BC=5, what is the length of segment BD?

For what value or values of x is the expression 3x/x^2-x undefined?

In a community of 800 people the rate at which a rumor spreads is jointly proportional to the number of people who have heard the rumor and the number of people who have not heard it. Given that the rumor is spreading at the rate of 20 people per hour whe...

square root of 7?