First, multiple-choice questions (3 points for each small question, 30 points for * * *)

1. If the following groups of numbers are three sides of a triangle, then a group of numbers that cannot form a right triangle is ().

A.2、3、4 B

C.6，8， 10 D

2. If two right-angled sides of a right-angled triangle are expanded to twice the original length at the same time, then the length of the hypotenuse is expanded to the original length ().

A. 1 times B.2 times?

C.3 times? D.4 times

3. Which of the following statements is correct? )

A. Given the length of three sides of a triangle, then

In a right triangle, the sum of squares of two sides is equal to the square of the third side.

C. In rtδ, if ∞, then

D. In rtδ, if ∞, then

4. As shown in the figure, the square area is known as 144 and 169, so the square area is ().