The given question is 8+13+18+...... which is in arithmetic progression . And for arithmetic series, we have to use the following formula for nth term .

Here a =8 , d=5
So we get

And the required expression for n=7 is


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9² = 12² + 15² - 2 (12) (15) cos (B)
81 = 144 + 225 - 360 cos(B)
81 = 369 - 360 cos (B)
360 cos (B) = 369 - 81
360 cos (B) = 288
cos (B) = 0.8
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Answer: Cosine B = 0.8
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12² = 15² + 9² - 2 (15)(9) cos (A)
144 = 225 + 81 - 270 Cos A
144 = 306 - 270 Cos A
270 Cos A = 162
Cos A = 3/5 or 0.6
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Answer: Cosine Angle A = 3/5
You literally just need to click yes then call it a day it’s simple don’t worry too much :D
I believe it is the ratio 3 : 1.
<u>18 students chose the turkey sandwich</u>.
Since the class has a total of 24 students, we can deduce that <u>6 students chose the vegetarian sandwich</u>.
This gives us a ratio of 18 : 6.
When simplified, we get a ratio of 3 : 1.