First since you know the radius:3 the perimeter of a full circle would be
2pi x 3 = 6 pi. But since it's only half it would be 3 pi.
6+3+3+3pi gets you 12+3 pi
a) Here, sum of two non-adjacent angles: 52 + 25 = 77
Now, ∠3 = 180 - 77 [ sum of all angles in a triangle is 180 ]
so, ∠3 = 103
Now, ∠3 + ∠4 = 180 [ Supplementary angles ]
So, ∠4 = 180 - ∠3
∠4 = 180 - 103 = 77
∠4 = 77 [ which is sum of two non-adjacent angles ]
....Hence proved.
b) m∠4 = 77
[ Solved in previous section ]
Hope this helps!
Answer:
Let p be the number of pens and let n be the number of notebooks.
4 notebooks + 3 pens cost $96 so 4n + 3p = 96
2 notebooks + 2 pens cost $54 so 2n + 2p = 54
We find n and p by solving the system of linear equations:
4n + 3p = 96
2n + 2p = 54
4n + 3p = 96
4n + 4p = 108 (we multiply this by 2 to cancel out 4n in both equations)
We then subtract the two equations:
(4n + 3p) - (4n + 4p) = 96 - 108
-p = -12
p = 12
So, a pen costs 12 dollars. We can use p to find n. We substitute 12 for p in one of our earlier equations:
2n + 2p = 54
2n + 2(12) = 54
2n + 24 = 54
2n = 30
n = 15
So, a notebook costs 15 dollars and a pen costs 12. Now, we need to find the cost of 8 notebooks and 7 pens:
8n + 7p = ?
8(15) + 7(12) = ?
120 + 84 = 204.
Thus, 8 notebooks and 7 pens cost 204 dollars (why is it so expensive lol).
The answer is C
negative times negative is equals to positive
