Answer:
Minimum umber of degrees that an equilateral triangle can be rotated before it carries onto itself = 120°
Explanation:
Refer the figure given below.
We need to find angle ADC to get the same equilateral triangle after rotation.
∠ADC = 180 - ( ∠DAC + ∠DCA) = 180 - ∠DAC - ∠DCA
∠DAC = ∠DCA = 0.5 x 60 = 30°
Substituting
∠ADC = 180 - 30- 30 = 180 - 60 = 120°
Minimum umber of degrees that an equilateral triangle can be rotated before it carries onto itself = 120°