3/4 = 0.75
10.5 / 0.75 = 14 samples can be made.
Area of a triangle is equal to 1/2 b(h) so since you already have the height and base, all you need to do is input it back into the equation:

(10)(13)
Multiply 10 & 13 to equal

(130)
Then take half of 130 to get
A = 65
(2,3) = (a,b)
(6,6) = (c,d)
D-B/C-A (To help remember, Dog Bites Cat's Arm)
6-3/6-2 = 3/4
Flip it
4/3 - the answer is c