In a right-angled triangle, the leg is 12, and the hypotenuse is 13. Find the bisector of the triangle
In a right-angled triangle, the leg is 12, and the hypotenuse is 13. Find the bisector of the triangle drawn from the vertex of the smaller angle.
AB = 12, BC = 13.
By the Pythagorean theorem in the triangle ABC we find AC.
The sum of the squares of the legs is equal to the square of the hypotenuse:
a ^ 2 + b ^ 2 = c ^ 2
12 ^ 2 + b ^ 2 = 13 ^ 2
b ^ 2 = 13 ^ 2 – 12 ^ 2
b ^ 2 = 169 – 144
b ^ 2 = 25
b = 5
We conclude that the angle ABC is a smaller angle.
cosABС = 12/13 = 0.92
according to the table of cosines, we find that the angle ABC = 22 °.
The bisector of a triangle is a segment that connects the vertex with the opposite side and divides the corresponding angle in half.
Hence half is 11 °.
We get a new triangle AВD.
Let’s find the length of the bisector:
ВD = AB * √ ((2 * BC) / (AB + BC))
ВD = 12 * √ ((2 * 13) / (12 + 13))
ВD = 12 * √ (26/25)
ВD = 12 * 1.019
ВD ≈ 12.23
Answer: ВD ≈ 12.23