CDE is an equilateral triangle formed on a side CD of a square ABCD. Show that ΔADE ΔBCE.


Given: CDE is an equilateral triangle formed on a side CD of a square ABCD.

In ΔADE and ΔBCE,


DE = CE (sides of equilateral triangle)


Now, ADC = BCD = 90° and EDC = ECD = 60°


Hence, ADE = ADC + CDE = 90° + 60° = 150°


And BCE = BCD + ECD = 90° + 60° = 150°


ADE = BCE


AD = BC (sides of square)


Hence, ΔADE ΔBCE (by SAS)


3
1