To be able to determine the bags of fertilizer that the gardener will need, let's first determine the area of the garden.
Since the shape of the garden is a trapezoid, we will be using the following formula:
[tex]\text{ Area = }\frac{1}{2}H(B_1+B_2)[/tex]We get,
[tex]\text{ Area = }\frac{1}{2}H(B_1+B_2)[/tex][tex]\text{ = }\frac{1}{2}(50)(70\text{ + 40)}[/tex][tex]\text{ = }\frac{1}{2}(50)(110\text{) = }\frac{50\text{ x 110}}{2}[/tex][tex]\text{ = }\frac{5,500}{2}[/tex][tex]\text{ Area = }2,75m^2[/tex]Let's determine how many bags of fertilizer will be used.
[tex]\text{ No. of Bags of Fertilizer = }\frac{\text{ Area of Garden}}{\text{ Area that a Bag of Fertilizer can cover}}[/tex]We get,
[tex]\text{ = }\frac{2,750(m^2)}{125\frac{(m^2)}{\text{bag}}}[/tex][tex]\text{ No. of Bags of Fertilizer = }22\text{ Bags}[/tex]Therefore, the gardener will be needing 22 Bags of Fertilizer.