Area of trapezium=(3+7)×10/2=50m², area of flower bed=½4×8=16m². Area of rectangle=15×10=150m².
Lawn area=150-50-16=84m².
(By splitting the trapezium into a rectangle (3×10) and a triangle (height=10, base=4) we get the area to be 30+20=50m². This is the same as taking the average of the base and top and multiplying by the height of the trapezium.)