In the acute triangle ABC, the lengths of three sides a, B and C are all integers, and a is less than B and less than C, a + B + C = 20

In the acute triangle ABC, the lengths of three sides a, B and C are all integers, and a is less than B and less than C, a + B + C = 20

According to the meaning of A2C, that is 20 > 2C  C20 / 3
So the value of C is 7 8 9
When C = 7, a + B = 13, that is, the average value of a and B is 6.5,
When a and B are integers, and ab is not true, so abandon
When C = 8, a + B = 12

In the acute angle △ ABC, if a = 2, B = 3, then the value range of side length C is___ ．

∵ a = 2, B = 3, so that △ ABC is an acute triangle, 32 + 22 ∵ C2, 22 + C2 ∵ 32, ∵ 5 ∵ C2 ∵ 13 ∵ 5 ∵ C ∵ 13, so the answer is: (5, 13)

In triangle ABC, ab = AC, angle c = 2, angle a, BD bisecting angle ABC, please find other isosceles triangle and choose one to explain the reason

Triangle abd and triangle BCD are isosceles triangle
Proof: Triangle abd is isosceles triangle
Because AB = AC, angle B = angle C
Because BD bisects angle ABC, angle abd = angle CBD
Because angle c = 2 angle a, angle abd = angle A
So Da = DB
So the triangle abd is an isosceles triangle