Ineed with #16 just a small explanation is fine

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ac=26 and ch=8, find bh.

Find the center of the circle that can be circumscribed about efg with e(4,4) f(4,2) g(8,2)

Amotorboat maintained a constant speed of 12 miles per hour relative to the water in going 45 miles upstream and then returning. the total time for the trip was 8.0 hours. use this information to find the speed of the current.