P=pages and H=hours, I’m assuming she read 20 pages, so C. h=20p should be correct, sorry if it wrong tho :)
Answer:

Step-by-step explanation:
Let's pretend the empty, white space in the middle is a triangle. A right triangle. then we just use the pythogerean theorem to get the a.

Answer: are they asking for the answer of the dotted line? If so, it might be 5 since it's the dotted line is opposing the side labeled 5cm.
Hope this helps:)
Step-by-step explanation:
You first work out the mean then for each number subtract the mean and square the result then work out the mean of those squared differences and take the square rot of that and you're done :)