40*1.2=48
1 represent the entire amount and .2 represents the tax added. When multiplied it would give you 48 as the final price.
Answer:

Step-by-step explanation:
How do we find the line that's perpendicular to another?
We find the negative reciprocal. So for example if our slope is 2, the negative reciprocal would be
.
So all u have to do is just add $1.28 and $0.54
Answer:

Step-by-step explanation:
We see that this is a rectangle triangle, and that the ZY side is the hypotenuse.
It's length is then square root of the sum of the squares of the other sides:

So, in this case:

The 8 and 3 numbers are easy to get from the graphic... and the order doesn't matter (8² + 3² = 3² + 8²).
That's an easy rule to remember.
I hope it helps.

the square root of two is irrational
the sqare root of four is rational