180 degrees in a triangle. so 180-90-31=59
1. C
L=1/2(Pxl)
L=1/2(20x9)
L=1/2(180)
L=90
SA=1/2(Pxl)+B
SA=90+5^2
SA=115
B, A, C, B.
The coordinates of C are (a+c, b)
Coordinates of midpoint of AC are (a+c/2, b/2)
Coordinates of BD are (a+c/2, b/2)
50% off means half price, so half of 49.98 is 24.99
the necklace now costs 24.99 dollars
