Find the hypotenuse AB of Right triangle ABC if AC = 12 and angle A = 45 degrees.

Since ∠BAC (the angle is more correctly denoted by three letters, the letter that is in the middle is the point of the apex of the angle) = 45 °, then ABS is also = 45 ° (the sum of the angles of the triangle is 180 °, 180 – 90 ° (straight line) – 45 ° = 45 °).

That. triangle and rectangular and isosceles – its legs are equal to each other.

AC – leg, it is 12, which means leg BC = 12.

Now the lengths of the two legs are known and, by the Pythagorean theorem, we find the hypotenuse:

AB = √144 + 144 (144 – square 12)

AB = √288 is not a whole square, an approximate value of 16.97, if you need an integer value, round up to 17.

Answer: AB = 16.97