Answer:
21 cm²
Explanation:
Applying,
A = (a+b)h/2............. Equation 1
Where A = area of the trapezium, a = length of the first parallel side, b = length of the second parallel side, h = height.
From the diagram
Given: a = 5 cm (5 grids), b = 9 cm (9 grids), h = 3 cm (3 grids)
Substitute these values into equation 1
A = 3(5+9)/2
A = 3(14)/2
A = 3×7
A = 21 cm²