Answer:
8m
Explanation:
We can convert the trapezium into a rectangle to make finding the area easier.
Say that the top side is 9m, and that the bottom side is 12m.
12 - 9 = 3
3/2* = 1.5
*Note that we are dividing by two to get the "overhang" of the bottom side.
Now that we have our overhang, we can find the length of the "t-rect"**.
**"T-rect" refers to a rectangle that has been formed by changing a trapezium into a rectangle.
12 - 1.5 = 10.5
9 + 1.5 = 10.5
The length of the t-rect is 10.5.
84/10.5 = 8
The height of the t-rect is 8m.
Since the height of the original trapezium is equal to the height of the t-rect***,
***Since we have only adjusted the length
this also means that 8m would also be the height of the original trapezium.
Now, there is a second way of doing this.
Find the median of 12 and 9.
9, 10, 11, 12
10, 11
The median is 10.5.
84/10.5 = 8
You get the same answer. These methods could be used as a solve-then-check method to another problem like these.
Hope this helps. Have a nice day.