How do you do this? Help please!! The x, y i put in arent correct btw. Thanks

If a 36 inch yardstick casts a 21 foot shadow, how tall is a building whose shadow is 168 feet? what is the scale factor

Luisa sells stuffed animals. she sells her stuffed elephant for $34.90, and the sales tax is 6% of the sale price. about how much is the sales tax on the elephant?

△abc is similar to △xyz. also, side ab measures 6 cm, side bc measures 18 cm, and side xy measures 12 cm. what is the measure of side yz ? enter your answer in the box.