# Calculus

posted by
**Fee** on
.

The burning candle

A candle is placed a distance l1 from a thin block of wood of height H. The block is a distance l2 from a wall as shown in Figure 7.1. The candle burns down so that the height of the flame, h1 decreases at the rate of 3 cm/hr. Find the rate at which the length of the shadow y cast by the block on the wall increases. (Note: your answer will be in terms of the constants l1 and l2.

Help please, and thanks!