13.
1st: split the 1 shape into 2 shapes. (spit across to where you see one right angle(top), and a trapezoid(bottom)
2nd: now what i did was fill that gap to where the total height is 9 and the total length is 7. ( if you don't want to do that it is fine )
3rd: for the top do 5 times 2 = 10
4th: for the bottom do 4 times 5 = 20
5th: add 10 (top) and 20 (bottom) = 30
A matrix is diagonal if

In other words, you want non-zero elements only when the indices of the row and the column are the same: the first element of the first row must be non zero, the second element of the second row must be non-zero, and so on. All other elements must be zero.
I think the answer is B, the one with a complete line and shaded to the bottom
What’s something goes up but never comes down?
Answer:
6
Explanation:
According to secant-secant theorem,
(PB)(PA)=(PD)(PC)
(7)(12)=(PD)(14)
NOW
84/14 = PD
PD = 6