Find the area, in square metres, of the trapezium whose bases and altitudes are as under:
(i) bases = 12 dm and 20 dm, altitude = 10 dm
(ii) bases = 28 cm and 3 dm, altitude = 25 cm
(iii) bases = 8 m and 60 dm, altitude = 40 dm
(iv) bases = 150 cm and 30 dm, altitude = 9 dm
(i) Area of trapezium = 
Length of bases of trapezium = 12 dm and 20 dm
10 dm = 1 m
Therefore length of bases in m = 1.2 m and 2 m
Similarly length of altitude in m = 1 m
Area of trapezium = 
Area of trapezium = 
m2
(ii) Area of trapezium = 
Length of bases of trapezium = 28 cm and 3 dm
10 dm = 1 m
Therefore length of bases in m = 0.28 m and 0.3 m
Similarly length of altitude in m = 0.25 m
Area of trapezium = 
Area of trapezium = 
m2
(iii) Area of trapezium = 
Length of bases of trapezium = 8 m and 60 dm
10 dm = 1 m
Therefore length of bases in m = 8 m and 6 m
Similarly length of altitude in m = 4 m
Area of trapezium = 
Area of trapezium = 
m2
(iv) Area of trapezium = 
Length of bases of trapezium = 150 cm and 30 dm
10 dm = 1 m
Therefore length of bases in m = 1.5 m and 3 m
Similarly length of altitude in m = 0.9 m
Area of trapezium = 
Area of trapezium = 
m2