Answer: 13.3 seconds
========================================================
Explanation:
Since triangle ABD is congruent to triangle CBD, this means the corresponding pieces AB and BC are the same length. Both are 70 feet.
Similarly, AD = DC = 60 ft.
The total length traveled is:
AB+BC+CD = 70+70+60 = 200 ft
We never use BD = 50 at all.
Divide this total distance over the speed of 15 ft per second, and we get 200/15 = 13.333 seconds approximately.
You are correct so far. You just need to round this value to the nearest tenth, as the instructions indicate. So you'll round to one decimal place. The value 13.333 turns into 13.3 which is the final answer.
