Ok
First factor out the first 2 terms as follows:-
y = 1/2(x^2 - 8x) + 21
Now complete the square on x^2 - 8x:-
y = 1/2[ (x - 4)^2 - 16] + 21
y = 1/2(x - 4)^2 - 8 + 21
y = 1/2(x - 4)^2 + 13 Answer
The earth is a spherical object, and you're correct, its radius is 3959 miles.
we know 71% of that is covered in water, that means 29% of that is not, 71%+29% = 100%.
well, let's recall that whatever% of anything is just (whatever/100) * anything.
now, how many square miles is its surface anyway?

since 71% is already covered with water, we only need the other 29% covered, what is 29% of 62694724π, well, is just
(29/100) * 62694724π.
Answer:
40º
Step-by-step explanation:
straight line: 180º
180-58-82=40
6 meters x 120 seconds = 720 meters
Hope this helps!