Help me with this question please :D

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

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?

Zack notices that segment nm and segment pq are congruent in the image below: which step could him determine if δnmo ≅δpqr by sas? (5 points) segment mo ≅ segment qr segment on ≅ segment qp ∠ n ≅ ∠ r ∠ o ≅ ∠ q