Math Problem Statement

Find k

Find k in the isosceles triangle with one angle measuring 111°.

Solution

The triangle in the image has a given angle of 111111^\circ and is part of an isosceles triangle since two of its sides are marked with equal lengths. Let's solve for the angle kk^\circ using the fact that the sum of the internal angles of a triangle is always 180180^\circ.

Step-by-step solution:

  1. Sum of angles in a triangle: The sum of the angles in any triangle is 180180^\circ.

  2. Given angle: One of the angles is 111111^\circ.

  3. Isosceles property: Since the triangle is isosceles, the two other angles are equal. Let these angles be kk^\circ.

  4. Equation for angle sum: k+k+111=180k + k + 111^\circ = 180^\circ Simplifying: 2k+111=1802k + 111^\circ = 180^\circ Subtract 111111^\circ from both sides: 2k=692k = 69^\circ Divide by 2: k=34.5k = 34.5^\circ

Thus, the angle k=34.5k = 34.5^\circ.

Let me know if you'd like more details or have any further questions!

Here are 5 related questions for you to consider:

  1. What is the total sum of the angles in a quadrilateral?
  2. How do you find the angles of a right triangle?
  3. What properties do equilateral triangles have in terms of their angles?
  4. How do you use the sine rule in non-right-angled triangles?
  5. What is the difference between isosceles and scalene triangles?

Tip: In any isosceles triangle, the two base angles are always equal. This is a key property that can help you solve many geometry problems quickly!

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Math Problem Analysis

Mathematical Concepts

Geometry
Triangles
Isosceles Triangles

Formulas

Sum of angles in a triangle: 180°
Equation: k + k + 111° = 180°

Theorems

Angle sum theorem
Isosceles triangle property

Suitable Grade Level

Grades 7-9