SOLUTION: I need help about right now. i really don't know what i am doing so please help me. the problem is this Slovel each pair of equation by subtitution x-y=7 x+y=9

Algebra ->  Circles -> SOLUTION: I need help about right now. i really don't know what i am doing so please help me. the problem is this Slovel each pair of equation by subtitution x-y=7 x+y=9       Log On


   

Question 13580: I need help about right now. i really don't know what i am doing so please help me. the problem is this
Slovel each pair of equation by subtitution
x-y=7
x+y=9

Answer by kusha(21) About Me  (Show Source):
You can put this solution on YOUR website!
ok let u be happy
u must use the formula of circumference when diameter = 7926 miles
radius = 3963 miles
and the circumference of circle with radius 3963 miles is (2x(22/7)x3963)
= 44x566.1 = 24904 approx = 24900 miles (rounded of to hundreds)
a term 24.3 rounded off becomes 24 but a term 24.6 rounded off becomes 25 . You can understand that we are trying to reach for the closest integer on either side. Similarly with 2431 the rounded off figure in hundreds is 2400 and with 2457 it is 2500
got it.