A waterslide is 4.2 m high and has a support 2.4 m tall. If a student reaches this support

when she is 3.1 m down the slide, how long is the slide?

Assuming that it's at the same angle the whole way, she goes 1.8 meters down in 3.1 meters down the slides, and if we divide 3.1 by 18 we can find how long the slide is for every 0.1 meter down, which is around 0.17. Multiplying that by 42, we get 7.23 (3 repeating) meters of the slide