D because perpendicular lines intersect at a right angle and D is the only shape with right angles.
97.8ft^2 but if you round it to the nearest 10 it will be 100ft^2
You will choose 1 cheese 3 different ways because there are three types of cheeses.
You will choose your topings 6 different ways. 4!/(2!2!) = 4*3/2 = 6
Therefore you will be able to get 6 * 3 different pizzas = 18 pizza combinations.
To confirm the toppings, suppose they are (M)ushrooms (P)epperoni (O)nions and (B)acon
M P
M O
M B
P O
P B
O B
Total 6.The order doesn't matter here. M O is the same thing as OM