How to know if the two triangles are similar

Atheater wants to build movable steps that they can use to go on and off the stage. they want the steps to have enough space inside so they can also be used to store props. how much space is inside the steps?

Including 6% sales tax, an inn charges $135.68 per night. find the inns nightly cost

Mis the midpoint of rq if rm equals 2x + 5 and mq equals 4x - 9 what is the length of rq