Exercise in class: 1, D 2, B 3. If two angles are equal, so are their complementary angles. 4. 1 false proposition 2 true proposition 3 false proposition
24.2 Proposition proof
1, a 2, is incorrect. When n=6, n-3n+7 = 25, and 25 is not a prime number. 3. It is known that two straight lines are parallel and the same angle is equal; The vertex angles are equal; Equivalent substitution.
24.3
1、B 2、B
24.4 Property Theorem of Parallel Lines
1,C 2,C 3。 If two angles are equal, they are acute angles 4 and 5.
Synchronous detection test questions
I. 1,B 2,A 3,C 4,B 5,A 6,C 7,B。
2. A triangle is equilateral if its three sides are equal.
10、30 1 1、 120 12、3 13、52 、 14、80 、
Innovation and improvement
1. 1,C 2,B,
Most of them are typed, and the title numbers are indicated. See for yourself. It's hard to type them out. ...