(1) Multiplies a number by an integer percentage, first by (the number) and (the numerator), and then by the product (plus a percent sign).

(2) Divide the semicircle into 180 equal parts, and the angle of each part is called (1).

(3) If the vertices and sides of two angles coincide, the two angles are equal in size.

(4) When A is divided by two digits, the quotient is 4, A is (4) times that of B, and the sum of A and B is (5) times that of B. ..

Second, painting.

? How to build a small bridge from point A to facilitate crossing the river? Draw a picture and write it briefly.

The angle 1 and the angle 2 are right angles.

Answer: 7_4_ 1