You need to find the area of the hexagon, and the area of the triangle.
The formula for the area of a triangle is

I hope this helps you a little.
Answer:
C
I may be wrong sorry if I am
First, add the price of the lamp and comforter.
$239.99
+ 89.95
=329.94
Then put 6 3/5 into a decimal:
3/5= .6
6.6%
Then change it from a % by dividing by 100.
6.6%= .066
Then multiply 329.94 by 1.066
329.94 x 1.066 = 351.716
= 351.72
So, yes. they paid the correct amount