As shown in the figure, it is known that ad is the middle line of △ ABC, ∠ ADC = 45 ° turn △ ADC over along the straight line ad, and point C falls at the position of point C ' As shown in the figure, it is known that ad is the middle line of △ ABC, ∠ ADC = 45 °, turn △ ADC over along the straight line ad, point C falls at the position of point C ', BC = 4, and find the square of the length of BC' I haven't thought about them for a long time

As shown in the figure, it is known that ad is the middle line of △ ABC, ∠ ADC = 45 ° turn △ ADC over along the straight line ad, and point C falls at the position of point C ' As shown in the figure, it is known that ad is the middle line of △ ABC, ∠ ADC = 45 °, turn △ ADC over along the straight line ad, point C falls at the position of point C ', BC = 4, and find the square of the length of BC' I haven't thought about them for a long time

In this case, c'dc = 90 degree;
And DC '= DC = BC / 2 = 2. So BC' ² = BD & #178; + c'd & #178; = 4 + 4 = 8