Can some show work on 1,2,& ,3

Use the pythagorean theorem method: a^2 + b^2 = c^2  

(sqrt stands for Square Root)

1. 5^2 + 12^2 = 169

sqrt(169) = 13

The length of the missing side is 13cm.

2. Since we don't have the length of side B we'll have to do this ourselves. We'll start with 16.

9^2 + 16^2 = 337

sqrt(337) = 18.3

It isn't 16 cuz we need it to equal 15. Let's try a lower number. This time we'll try 12.

9^2 + 12^2 = 225

sqrt(225) = 15

So, the length of the missing side is 12cm.

3. 8^2 + 6^2 = 100

sqrt(100) = 10

The length of the missing side is 10km.