The best choice is
B.
_____
The black triangle is on the end of one of the rectangular faces, the end that meets up with the double line on the triangular base.
Answer:
See below.
Step-by-step explanation:
1.) 5√6
2.) 6√2
3.) 3√7
To solve this without the use of a calculator, split the given number into a series of products (numbers multiplied) and look for pairs.
Look at the attached example of Problem 1 to get a better idea of what I mean.
8x-10y=-23
9x+10y=-16
(8x+9x)+(10y-10y)=(-23+(-16))
17x+0y=-39
x=-39/17
8(-39/17)-10y=-23
-312/17-10y=-23
-10y=-23+312/17
-10y=-79/17
y=79/170