Acalculator showed the answer to a multiplication problem as 2.8e–4.
which expression is equivalent to 2.8e–4?

2.8 x 104

2.8 x (-4)

2.8¯4

2.8 x 10¯4

Use pythagorean’s theorem and find the missing side lengths of the two smaller triangles and add them together
13^2 - 12^2 = 5
15^2 - 12^2 = 9
5+9 = 14
14 is the length of each side of the square
14^2 + 14^2 = 19.8
19.8 is the diagonal length of the inside if the square