Answer:
31200
Explanation:
pyramid surface area = base x 2 x first triangle surface area x 2 x second triangle surface area
20 x 2 x 13 x 2 x 1/2 x 12 x 10 x 1/2 =
40 x 13 x 12 x 5 = 40 x 60 x 13 = 2400 x 12 = 31200
the area is 31200
hope it's correct