Answer:
EF = 
Step-by-step explanation:
Since this triangle is right, we can use the pythagorean theorem to find the missing side length. The pythagorean theorem states that the square of the hypotenuse(DE) is equal to the sum of the squares on the legs(DF, EF). We can write:
DE^2 = DF^2 + EF^2
and substitute the values:
17^2 = 13^3 + EF^2
289 = 169 + EF^2
EF^2 = 120
EF = 
Answer: When dividing by 100, move the decimal two places to the left
Step-by-step explanation: 0.1 / 100 = 0.001
There are 2 zeros in 100 so you move the decimal to the left 2 times when you are dividing. When you move the decimal 2 times in 0.1 you get 0.001