Answer:
A. B is correct
B. A is correct
C. B is correct
Explanation:
Area of triangle: A = 1/2bh
A. Area of each triangle: A = 1/2 x 11.5 x 12 = 69
Total surface areas = 4(area of triangle) + area of square = 4(69) + 12^2 = 420
So A is incorrect and B is correct
B. Area of triangle: A = 1/2 x 13.9 x 16 = 111.2
Surface area = 4(area of triangle) = 4(111.2) = 444.8
So A is correct and B is incorrect
C. Area of triangle with base of 10: A = 1/2 x 10 x 7 = 35
Area of triangle with base of 8.1: A = 1/2 x 8.1 x 16 = 64.8
Total surface areas = 2(area of triangle base of 10) + 2(area of triangle base of 8.1) + area of rectangle = 2(35) + 2(64.8) + (10x8.1) = 280.6
So A is incorrect and B is correct.