Answer:
For a trapezium of height H, parallel side 1 X, and parallel side 2 Y, the area is:
A = (1/2)*H*(X + Y)
with this we can complete the table.
a)
Here we know:
X = 7cm
Y = 11cm
H = 6cm
Then: A = (1/2)*6cm*(7cm + 11cm) = 54 cm^2
b)
Here we know:
X = 8 m
Y = 10 m
A = 126 m^2
Then:
126 m^2 = 0.5*H*(8m + 10m)
126 m^2 = H*9m
126 m^2/9m = H = 14m
Then the height of this trapezoid is 14m
c)
Here we know:
X = 5mm
H = 8mm
A = 72 mm^2
Then:
72 mm^2 = 0.5*8mm*(5mm + Y)
72 mm^2 = 4mm*(5mm + Y)
72mm^2/4mm = 5mm + Y
18 mm = 5mm + Y
18mm - 5mm = Y
13 mm = Y
Then the parallel side 2 is 13 mm long.