Given: △abc, d∈ ab, e∈bc, f∈ac, de∥ac, ad∥fe, ad=6, de=5, ab=17. find: ac

AC = 7.73

Step-by-step explanation:

∵ DE // AC

∴ m∠BDE = m∠BAC ⇒ corresponding angles

∴ m∠BED = m∠BCA ⇒ corresponding angles

∵ ∠B is common angle

∴ Δ BDE is similar to Δ BAC

∴ BD/BA = DE/AC = BE/EC

∵ AD = 6 and AB = 17

∴BD = 17 - 6 = 11

∵ DE = 5

∴ 11/17 = 5/AC

∴ AC = (5 × 17) ÷ 11 = 7.7272 ≅ 7.73

hello from mrbilldoesmath!

answer:

x - 3

discussion:

x^2 - 9 = (x-3) (x+3)   so

(x^2-9)/ (x + 3) = x-3

you,

mrb

12

step-by-step explanation:

a triangle's   full angle is 180 degrees so 180 - 156 = 24. 24/2=12