The formula for a trapezoid relates the area a, the two bases, a and b, and the height, h. a=12h(a+ b. solve for h.

Small correction, the area of a trapezoid is , not . So I will be solving for the prior.

Firstly, divide both sides by (a+b):

Next, multiply both sides by 2 and your answer is

distance covered by pamela in 9 l of fuel = 99km

let us apply unitary method here.

distance covered by pamela in 1 l of fuel =99/9 =11 km

now let us find distance covered by pamela if she has 12 l of fuel.

distance covered in 12 l = distance covered in 1 l of fuel * 12

we know that distance covered by here in 1 l is 11 km.

so distance covered in 12 l of fuel = 11*12 = 132 km.