Total weight=number of pennies times weight of 1 penny
total weight/weight of 1 penny=number of pennies
636.3/3.03=210
210 pennies
In any trapezoid, the area is given by

where B and b are the two bases, and h is the height. You're given all these elements already, so you only need to plug the values in:

You have to isolate the (a) so you multiply the 2/3 by 3/2 and you have to do that to the right side. So -24 times 3/2 equals to -36. Therefore, a=-36.
Answer:
first box is 4/5 and the second box (=) is 7/15