Problem: Each side of triangle A B C A B C 12 1 2 D D A A B C B C E E A D A D B E B E
Answer Choices:
A. 18 1 8 ​
B. 28 2 8 ​
C. 6 6
D. 63 6 3 ​
E. 98 9 8 ​ Solution:
B E ‾ 2 = B D ‾ 2 + D E ‾ 2 , B D ‾ = 6 , D E ‾ = 1 2 D A ‾ = 1 2 ⋅ 6 3 = 3 3 B E 2 = B D 2 + D E 2 , B D = 6 , D E = 2 1 ​ D A = 2 1 ​ ⋅ 6 3 ​ = 3 3 ​ B E ‾ 2 = 36 + 27 B E 2 = 3 6 + 2 7