Question

If a triangle is an isosceles triangle, then it has two sides of equal length. If a triangle has two sides of equal length, then it has two angles of equal measure
Conclusion:
If a triangle is an isosceles triangle, then it has two angles of equal measure.



The argument is not valid because the conclusion does not follow from the premises.

The argument is valid by the law of syllogism.

The argument is not valid because the premises are not true.

The argument is valid by the law of detachment.

Answer 1

we know that

The Law of Syllogism says that if the following two statements are true:

(1) If p -------> then q .

(2) If q-------> then r .

Then we can derive a third true statement:

(3) If p--------> then r .

In this problem

(1) If a triangle is an isosceles triangle, then it has two sides of equal length

(2) If a triangle has two sides of equal length, then it has two angles of equal measure

Let

p-------> the statement " an isosceles triangle"

q--------> the statement " has two sides of equal length"

r--------->  the statement "has two angles of equal measure"

Then (1) and (2) can be written

1) If p , then q .

2) If q , then r .

So, by the Law of Syllogism, we can deduce

3) If p , then r

or

If a triangle is an isosceles triangle, has two angles of equal measure

therefore

the answer is

The argument is valid by the law of syllogism.

Answer 2

It is valid through syllogism