Okay, this is a very visual problem, and I will try to solve it the best I can with words.
As I understand, we have a rectangle, and a triangle inside of it. The dimensions of the rectangle are 8cm X 7cm. The triangle shares the side AD with the rectangle, so it has a base size of 7cm, and it...

This equation really just wants you to plug in the values it gives you. In this case, it gives you the value of x, which is 2, and it gives you the value of z, which is 13. So wherever we see an x in the above equations, we are gonna put a two there instead, so we do this:
y = 2+z
All...

I assume you are just referring to simple rounding, and in that case, you need to know two things:
1. Are we rounding up or down?
2. What place are we rounding to?
The answer to the first question is one that is easily answered. Generally, unless stated otherwise, we round numbers that...