Math Problem Statement

if the triangle has angles alpha=45, beta=45, gamma=90, a=4cm, b=4cm, c=root of (aa+bb), and we construct the axes of the angles of each angle, we get the triangle KLM , what are the sizes of the angles?

Solution

Given the problem, we have a right-angled isosceles triangle with angles α=45\alpha = 45^\circ, β=45\beta = 45^\circ, and γ=90\gamma = 90^\circ. The sides opposite these angles are a=4cma = 4 \, \text{cm}, b=4cmb = 4 \, \text{cm}, and the hypotenuse c=a2+b2=42+42=32=42cmc = \sqrt{a^2 + b^2} = \sqrt{4^2 + 4^2} = \sqrt{32} = 4\sqrt{2} \, \text{cm}.

When the angle bisectors of a triangle are constructed, they meet at the incenter of the triangle. The angles of the new triangle formed by the intersection points of the angle bisectors, typically denoted as triangle KLMKLM, are half the sum of the angles of the original triangle.

Calculating the angles of triangle KLMKLM:

  1. Angle at KK (opposite α=45\alpha = 45^\circ):

    • The angle at KK will be half the sum of the other two angles β+γ\beta + \gamma: K=12×(45+90)=1352=67.5\angle K = \frac{1}{2} \times (45^\circ + 90^\circ) = \frac{135^\circ}{2} = 67.5^\circ
  2. Angle at LL (opposite β=45\beta = 45^\circ):

    • The angle at LL will be half the sum of the other two angles α+γ\alpha + \gamma: L=12×(45+90)=1352=67.5\angle L = \frac{1}{2} \times (45^\circ + 90^\circ) = \frac{135^\circ}{2} = 67.5^\circ
  3. Angle at MM (opposite γ=90\gamma = 90^\circ):

    • The angle at MM will be half the sum of the other two angles α+β\alpha + \beta: M=12×(45+45)=902=45\angle M = \frac{1}{2} \times (45^\circ + 45^\circ) = \frac{90^\circ}{2} = 45^\circ

Therefore, the angles of the triangle KLMKLM are:

  • K=67.5\angle K = 67.5^\circ
  • L=67.5\angle L = 67.5^\circ
  • M=45\angle M = 45^\circ

These angles add up to 180180^\circ, confirming the calculation.

Would you like more details on this topic, or do you have any other questions?

Related Questions:

  1. What is the significance of the incenter in a triangle?
  2. How do you calculate the length of the incenter in an isosceles right triangle?
  3. What is the relationship between the circumcenter and the incenter in a right triangle?
  4. How do the angles of a triangle affect the properties of its angle bisectors?
  5. How do you construct the triangle KLMKLM geometrically?

Tip:

In any triangle, the angle bisectors always intersect at the incenter, which is equidistant from all the sides of the triangle.

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Math Problem Analysis

Mathematical Concepts

Geometry
Triangle Properties
Angle Bisectors
Right-Angled Triangle
Isosceles Triangle

Formulas

Pythagorean theorem: c = √(a² + b²)
Angle sum of a triangle: α + β + γ = 180°
Angle bisector theorem: The incenter angles are half the sum of the opposite angles.

Theorems

Pythagorean Theorem
Angle Bisector Theorem
Sum of Angles in a Triangle

Suitable Grade Level

Grades 9-12