SOLUTION: ratio of number of sides of 2 regular polygon is 5:6. & ratio of there each interior angle is 24:25.find the number of sides of each polygon?

Algebra ->  Polygons -> SOLUTION: ratio of number of sides of 2 regular polygon is 5:6. & ratio of there each interior angle is 24:25.find the number of sides of each polygon?      Log On


   



Question 669167: ratio of number of sides of 2 regular polygon is 5:6. & ratio of there each interior angle is 24:25.find the number of sides of each polygon?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
your solution is that:
n1 = 10
n2 = 12
a1 = 144
a2 = 150

n = number of sides.
a = measure of the interior angle.
1 is for polygon number 1
2 is for polygon number 2

there's a lot of arithmetic involved, but the basics of the solution is as follows:

you have n1%2Fn2+=+5%2F6

you have a1%2Fa2+=+24%2F25

the formula for a1 is %28%28n1-2%29+%2A+180%29+%2F+n1

the formula for a2 is %28%28n2-2%29+%2A+180%29+%2F+n2

since the ratio of a1%2Fa2+=+24%2F25, you can substitute for a1 and a2 in that ratio to get:

%28%28%28n1-2%29+%2A+180%29+%2F+n1%29+%2F++%28%28%28n2-2%29+%2A+180%29+%2F+n2%29+=+24%2F25

you can cross multiply to get:

25+%2A+%28%28%28n1-2%29+%2A+180%29+%2F+n1%29+=++24+%2A+%28%28%28n2-2%29+%2A+180%29+%2F+n2%29

you have 1 equation in 2 unknowns.
you can reduce the number of unknowns by taking the ratio of n1 to n2 and solving for n2.

the ratio of n1 to n2 is given as n1%2Fn2+=+5%2F6

from that, you can solve for n2 to get n2+=+6+%2A+n1+%2F+5

you now substitute 6+%2A+n1+%2F+5 for n2 in the equation of 25+%2A+%28%28%28n1-2%29+%2A+180%29+%2F+n1%29+=++24+%2A+%28%28%28n2-2%29+%2A+180%29+%2F+n2%29 and solve for n1.

once you find n1, you can then find n2 and you can then find a1 and a2.

the math is tricky but the process works and i was able to find n1 = 10 and n2 = 12.

from that i was able to get a1 = 144 and a2 = 150.

the ratios hold up so the solution is good.