The steps matter on the size of the number.
The area of a triangle is half the product of the base and the height.
Since multiplication is commutative, the following expressions are equivalent:

So, option D is correct
Area=pir^2
diameter/2=radius
diameter=9
d/2=9/2=4.5=r
area=pi4.5^2
area=pi20.25
aproxpi=3.14
area=63.585
round hundreth
area=63.59
answer is 63.59cm^2