Answer:
For all of these triangles apply the formula;
A = BH x 1/2
Where 'B' represents the base, 'H' stands for the height, and 1/2 just means to divide the product of the two lengths (base x height) by 2.
1.
Base = 9.1
Height = 31.2
Plug into formula:
A = BH x 1/2
A = 9.1(31.2) x 1/2
A = 283.92 x 1/2
A = 283.92/2
A = 141.96 square centimetres.
2.
Base = 5
Height = 3 3/4 which can be considered 3.75
Plug into formula:
A = BH x 1/2
A = 5(3.75) x 1/2
A = 18.75 x 1/2
A = 18.75/2
A = 9.375 square kilometres.
3.
Base = 2.4
Height = 3.2
Plug into formula:
A = BH x 1/2
A = 2.4(3.2) x 1/2
A = 7.68 x 1/2
A = 7.68/2
A = 3.84 square inches.
4.
Base = 11
Height = 60
Plug into formula:
A = BH x 1/2
A = 11(60) x 1/2
A = 660 x 1/2
A = 660/2
A = 330 square millimetres.
5.
Base = 10
Height = 13 1/2 which can be considered 13.5
Plug into formula:
A = BH x 1/2
A = 10(13.5) x 1/2
A = 135 x 1/2
A = 135/2
A = 67.5 square feet.