The sum of all interior angles in a polygon is
180(n-2), where n = sides, well, this is a QUADrilateral, so it has 4 sides, so the total is 360°.
now, let's find what angle C is first,

now, recall the "inscribed quadrilateral conjecture", where opposite angles are "supplementary angles", thus
To find the number of CD on sale, we can set an equation.
Let y be the number if CD.
As she bought 40%, the amount she bought= 40%y
The equation:
40%y = 80
0.4y = 80
y = 80÷0.4
y=320
Therefore there were originally 320 CDs.
Hope it helps!
Answer:
The answer is 22.
Step-by-step explanation:
Just well use a calculator. If you don't have that then use PEMDAS. Hope it helps.
you have negative -12
turn this into a positive (12)
12 plus 18
= 30
If you estimate
7 times 7=49 so the square root of 46 is less than 7
6 times 6= 36 so the square root of 46 is more than 6
so if you do it on a calculator the answer is 6.78