math b
posted by manda .
if sinx=(4/5), where 0 degrees<x<90 degrees, find the value of cos (x+180)
25+25+100+n=250
since x is in the first quadrant, then x+180ยบ is in the third quadrant, and cos(x+180) = =cos x
You should recognize the 3,4,5 rightangled triangle and cosx = 3/5
so cos(x+180)=3/5
3x+y=90+2x+y=90
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