If the perimeter of ΔACD is 9+3√3, what is the perimeter of equilateral triangle ΔABC? Answers.
A) 9  B) 18 − 3 √ 3  C) 18  D) 18 + 3 √ 3  E) 27

Rationale: the altitude of an equilateral triangle is side * √ 3 / 2 . as perimeter of triangle acd is 9 + 3 √ 3 , ac + cd + ad = ( side + side / 2 + side * √ 3 / 2 ) = 9 + 3 √ 3 or side = 6 . perimeter of equilateral triangle , abc is 3 ( side ) or 18 . answer : ( optionc )
Answer: C