Answer:
Number 4: Using Pythagoras Theorem,

Number 5:

3:
It is a right triangle
4:
Not a right triangle
For the last one:

Rounded down (because the answer needs to be a whole number) is 21
67 because 24 isnot 50 yet so you would keep 67 how it is but if it was 50 or more then you would round it up to 68
False. In order to have an inverse, your function must pass the horizontal line test. The graph fails the test.