Determina la circunferencia de un circulo cuya medida del diametro es 16.5 cm

Aline parallel to a triangle's side splits ab into lengths of x - 5 and x + 2. the other side, ac, is split into lengths of x and x + 12. what is the length of ac? a) 12 b) 24 c) 36 d)

If the cost to mail a package is an initial $5 and $0.28 for every pound the total cost to mail a package was $11.27, how much did the package weigh?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.