1 hour equals 70 miles so 70 times 4 equals 280 and half of 70 is 35 since you traveled 4.5 hours and 280+35 equals 315
HI, I drew & explained it below. I used the sine trig function to find the diagonal length and then used the pythagorean to find the missing length. Hope this helps :)
52 is the answer to this question
The slope f'(x) = [f(4) - f(2)]/(4-2)≥3,
so [f(4) - 13]/2 ≥3
f(4) -13 ≥ 6
f(4)≥19, so it can be as small as 19.