1). Take a little e on MB, make MA=ME, draw an arc with points A and E as the center and any length greater than MA as the radius. Two arcs must intersect at one point, connecting the intersection point and point M, which is the perpendicular of AB.

2) Take a point f on the CD, make MF=MD, and draw an arc with a radius greater than 1/2DF with f and d as the center. Two arcs must intersect at one point, connecting the intersection point and point m, which is the vertical line of CD.

3. The painting method is the same as that of the second question. I'd love to. Draw it myself. The final finding is that the two line segments are equal (this is what you will learn later, and you will often use it! )