A multiple-choice question (this big question *** 24 points)

1. Take the following groups as three sides of a triangle, where () (A) 17,15,8 (b)1/3, 1/4, 1/5 can form a right angle.

2. If the degree of one angle of a triangle is equal to the sum of the degrees of the other two angles, then this triangle must be () (a) acute triangle (b) right triangle (c) obtuse triangle (d) isosceles triangle 3. In the following groups of line segments, which can form a triangle is ().

(a)5 12， 13(b)5 12，7(c)8 18，7 (d) 3，4，8 4。 As shown in the figure, in Rt△∠BAC, ∠ C.

(ADC = Germany (B)≈ADC =≈ Ade (C)≈ Debu = 90(D)≈BDE =≈ Dee.