If the perimeter of ΔACD is 9+3√3, what is the perimeter of equilateral triangle ΔABC? Select the correct option:  A) 9  B) 18−3√3  C) 18  D) 18+3√3  E) 27
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:(Option18)
<result>C</result>
If the perimeter of ΔACD is 9+3√3, what is the perimeter of equilateral triangle ΔABC?