Question

A builder makes drainpipes that drop 1 cm over a horizontal distance of 30cm to prevent clogs a certain drainpipe needs to cover a horizontal distance of 700cm whats is the length of the drainpipe? round your answer to the nearest tenth of a centimeter

Answer 1

The correct Answer for Khan Academy is 700.4

Explanation:

Answer 2

Length of the drainpipe = 700.7 cm

Explanation:

Given a builder makes drainpipes that drop 1 cm over a horizontal distance of 30cm to prevent clogs. The ratio of the vertical drop to the horizontal distance covered is
`(1)/(30)` cm.

The angle of inclination,

tan(θ) =
`(1)/(30)`

θ = 1.9º

By trignometric ratio,

cos(θ) =
`(horizontal distance)/(length of the drainpipe)`

length of the drainpipe =
`(700)/(cos(1.91))` =
`(700)/(0.999)`

length of the drainpipe = 700.7 cm