The ratio between Area of D and Area of C is 28:7.
That means the simplified version is 1:4.
From our ratio, we can derive that the scale factor is 4.
Answer: Choice B
They did not perform the cross multiplication properly
The correct step should be m*24 = 8*15 which solves to m = 5
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Explanation:
In general, if we had the equation A/B = C/D, then it cross multiplies to A*D = B*C. We refer to this as cross multiplication because of the shape made when we connect the terms (to figure out what multiplies with what). The diagram below shows what I mean.
So that's why m/8 = 15/24 cross multiplies to m*24 = 8*15
Simplifying things a bit leads to 24m = 120. Then we divide both sides by 24 to fully isolate m and we get m = 120/24 = 5. Therefore, m = 5.
<span>We know that sin^2(x) = 1 - cos^2(x), so
2 - 2 cos^2(x) = 2 + cos(x)
cos(x) + 2 cos^2(x) = 0
One immediate possibility is that cos(x) = 0, in which case x = Pi/2 or
3pi/4. If cos(x) is not zero, then divide both sides by cos(x) to obtain
cos(x) = -1/2
which gives x = 2Pi/3 and x = 4Pi/3.
So your solutions are
Pi/2, 3Pi/4, 2Pi/3, and 4Pi/3
Hope this helps :D</span>