Can you use the Cosine Law, c^2=a^2+b^2-2ab.cos C, to find the length of the hypotenuse in a this right triangle if you know the lengths of the legs of the triangle ? Why ?

of course. cos 90º = 0

so now you just have the Pythagorean Theorem.

No, you cannot use the Cosine Law to find the length of the hypotenuse in a right triangle if you only know the lengths of the legs.

The Cosine Law can be used to find the length of any side of a triangle if you know the lengths of the other two sides and the angle between them. However, in a right triangle, one of the angles is always 90 degrees, which means the Cosine Law does not apply.

Instead, to find the length of the hypotenuse in a right triangle, you can use the Pythagorean theorem, which states that in any right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other two sides.

No, you cannot use the Cosine Law to find the length of the hypotenuse in a right triangle. The Cosine Law is used to find the lengths of the sides or the measures of the angles in a general triangle (not specifically a right triangle).

In a right triangle, you can use the Pythagorean Theorem to find the length of the hypotenuse if you know the lengths of the legs. The Pythagorean Theorem states that in a right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the two legs. Mathematically, it can be represented as:

c^2 = a^2 + b^2

Where c represents the length of the hypotenuse, and a and b represent the lengths of the legs.

Therefore, to find the length of the hypotenuse in a right triangle, you do not need to use the Cosine Law; you can simply use the Pythagorean Theorem.