D. Apply Your Knowledge (3 pts)

10. Returning to the roof problem in Ex. 4, a builder can only buy boards for rafters that are 18 feet long. The builder is building another house that is 30 feet wide (Remember to use half of 30 or 15 for the run). How tall will the attic be at its highest point? Show your work as it is done in Ex. 4 and round to the nearest tenth of a foot.

Ex. 4 In the side view below of the roof of a house, notice a is the RISE of the roof, b is the RUN of the roof, and c is the RAFTER (hypotenuse) of the triangle with side lengths a and b. Building a house, a homeowner wants to be able to walk in the attic and would like the rise to be 7 feet. The width of the house is 30 feet so the run in the given triangle is 15 feet. The builder needs to know how long the rafters should be to the nearest tenth of a foot. Show work and include units of measurement to help the builder.

Rafter Rise Run