Question

In ∆ABC, cos C = `12/13` and BC = 24, then AC = ?

Answer 1

cos C = `12/13`     .....(i) [Given]

In ∆ABC,

Let ∠ABC = 90°

∴ cos C = `"BC"/"AC"`    .....(ii) [By definition]

∴ `"BC"/"AC" = 12/13`  ......[From (i) and (ii)]

∴ `24/"AC" = 12/13`

∴ `(24 xx 13)/12` = AC

∴ `312/12` = AC

∴ AC = 26 units