first, since its a rectangle, the parallel sides are equal making the top of the rectangle 9cm. the to fins the sides, we do 9+9( because of the sides o the rectangle) which gives us 18. then we need to do 28-18 to find out how much both the other sides of the rectangle are, which is 10. now we divide that by 2 since we want one for each side main the measurements for the rectangle are 9cm by 5 cm. now since to find out the area of aa trapezium, we use the formula A=1/2(a+b)h which means we add the 2 parallel sides of the rectangle which are 5 and 9. we got the 9 from figuring out the rectangle remember? now 9+5=14. next we times it by the height which will be 6 since 11-5 is 6. we got the 5 from figuring out the rectangle above. now 14x6 is 84. however what about then 1/2 part in the formula?. well, all we do now is divide 84 by 2 which gives us 48
REMEMBER: The formulae for working out the area of a trapezium is 1/2x(a+b)xh
