The diagram shows a lawn with a fence along one edge. 12 m
17 m
Fence
20 m
One can of weedkiller can cover 100 square metres.
Each can costs £19.75
Work out the total cost of the cans of weedkiller needed to cover the lawn.
You must show some working.

the surface area is 124cm²

step-by-step explanation:

length: 4cm

width: 9cm

height:   2cm

step-by-step explanation: given equation a = h(b 1+b 2)

also we are given values of a, h and b 1 as :

a = 16, h = 4, and b 1 = 3.

in order to solve it for b 2, we need to plug the given values of   a, h and b 1 .

therefore, plugging values of   a, h and b 1   in given equation, we get

16 = 4( 3 + b 2)

first dividing both sides by 4, we get

4 = 3 + b 2

subtracting 3 from both sides, we get

4 -3 = 3 -3 + b 2

1 = b 2.