so basically you're trying to find the third side. I'd like you to meet this new equation called the Pythagorean theorem. The equation is basically a²+b²=c².
So here is where you use the formula:
Replace x and y with 8 and 10
8²+10²=c²
Now simplify the equation
8² = 64
10² = 100
64+100=c²
164=c²
now you have to remove that ² from c. So basically you cancel it by square rooting it. But if you square root one side, you have to square root the other side.
√164 = √c²
√ and ² cancel each other out...
c = √164
√164 = 12.8
c= 12.8
Wait! we're not done yet cause now you have to find the perimeter of the triangle.
12.8+8+10
=30.8
Hope this helps!
