Scale Factor is: When you divide the old shape by the new shape (explanation is here)
Step-by-step explanation:
When you have 2 shapes (lets say Y is the old shape and F is the new shape) you would divide the old shape (Y) by the new shape (F)
Another example: lets say shape F is 12 cm and shape Y is 7 cm (F being the old and Y being the new shape) you would divide 12 and 7 to get the answer to that problem
The formula for the area of a trapezoid is A = a+b/2 * h. So just plug in the dimensions. A = 5 + 3/2 * 5 A = 8/2 * 5 A = 4 * 5 A = 20 units² I hope this helps love! :)