253+147 what does it equal tell me the answer down below and you will get 21 points

In right ∆abc shown below, the midpoint of hypotenuse ac is located at d and segment bd is drawn.if ab = 12 and bc = 16, then explain why bd = 10. hint: consider what you know about the diagonals of a rectangle.

Tom drove 206 miles in 3.9 hours. estimate his average speed.

1/2+1/6-3/4 simplify the given expression leaving the answer in improper fraction form.