Answer:
C. 14cm
Step-by-step explanation:
The square of the longest line, in an obtuse triangle, is greater than the sum of the squares of the other two sides. So it is appropriate for equivalent legs to have a length
L^2 + l^2=2l^2
14^2+14^2=20^
196+196=400
392=400 400
The result: 14cm
