Hey, so we will use the formula - A squared + B squared = C squared.
~ So we already have 7 cm and 5 cm down. We can just substitute it in our formula.
~ So for now, it’s, 7+5= C, but we need to square these numbers. So it now becomes 49+25=C squared
~ So 49+25= 74
~ So C=74
~ Now we just need to find the square root of 74
~ And that gives you around 8.6 as an answer.
Hope this explanation will help you in the future :), have a great day