surface area of a triangle is 1/2 x base x height.
1/2 x 10 x 12 = 60 square inches.
there are 4 triangular sides: 60 x 4 = 240 square inches
area of the base = 10 x 10 = 100 square inches
total surface area = 240 + 100 = 340 square inches
answer: 340 square inches
