ANSWER
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Ratio of 8th graders to 7th graders = 3 : 2
Let the number of graders be 3x and 2x
Number of 8th graders = 18
So , 3x = 18
x = 18/3 = 6
Number of 7th graders = 2 × 6 = 12
Ratio of 6th graders to 7th graders = 5 : 4
Let the number of graders be 5a and 4a
Number of 7th graders = 12
So , 4a = 12
a = 12/4 = 3
Number of 6th graders = 5×3 = 15 ANS
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#BE BRAINLY
Answer:
Step-by-step explanation:
Here we are given that the value of sinA is √3-1/2√2 , and we need to prove that the value of cos2A is √3/2 .
<u>Given</u><u> </u><u>:</u><u>-</u>
•
<u>To</u><u> </u><u>Prove</u><u> </u><u>:</u><u>-</u><u> </u>
•
<u>Proof </u><u>:</u><u>-</u><u> </u>
We know that ,
Therefore , here substituting the value of sinA , we have ,
Simplify the whole square ,
Add the numbers in numerator ,
Multiply it by 2 ,
Take out 2 common from the numerator ,
Simplify ,
Subtract the numbers ,
Simplify,
Hence Proved !
The sum of the interior angles of any polygon is given by (n-2)180°, where n is the number of sides.
Also sum of all the exterior angles of any polygon is 360°
Given (n-2)180° = 3(360°)
=> n-2 = 6
=> n = 8.
Hence the number of sides of a polygon is 8