Math Problem Statement

Answer

The figure below shows two intersecting lines. Find the value of x, y, z. Give reasons for your steps.

Solution

Let's solve for the values of xx, yy, and zz using the properties of angles formed by intersecting lines.

Step 1: Identify angle relationships

  1. The two intersecting lines form vertically opposite angles, which are always equal. Hence: 3x10=y(since they are vertically opposite angles)3x - 10^\circ = y \quad \text{(since they are vertically opposite angles)} Similarly, for the angles on the other side of the intersection: 2x+15=z(since they are vertically opposite angles)2x + 15^\circ = z \quad \text{(since they are vertically opposite angles)}

  2. The adjacent angles along a straight line must add up to 180180^\circ because they are supplementary. Therefore: (3x10)+(2x+15)=180(3x - 10^\circ) + (2x + 15^\circ) = 180^\circ Simplifying this equation: 5x+5=1805x + 5^\circ = 180^\circ Subtract 55^\circ from both sides: 5x=1755x = 175^\circ Divide by 5: x=35x = 35^\circ

Step 2: Find yy and zz

Now that we know x=35x = 35^\circ, we can substitute this value back into the expressions for yy and zz.

  1. For yy: y=3x10=3(35)10=10510=95y = 3x - 10^\circ = 3(35^\circ) - 10^\circ = 105^\circ - 10^\circ = 95^\circ

  2. For zz: z=2x+15=2(35)+15=70+15=85z = 2x + 15^\circ = 2(35^\circ) + 15^\circ = 70^\circ + 15^\circ = 85^\circ

Final Answer:

  • x=35x = 35^\circ
  • y=95y = 95^\circ
  • z=85z = 85^\circ

Reasons for Steps:

  • Vertically opposite angles: These are equal, so we used this to relate yy and zz to the given angles.
  • Supplementary angles: Angles on a straight line add up to 180180^\circ, which allowed us to form an equation to solve for xx.

Let me know if you want further clarification or details on any part of the solution.

Related Questions:

  1. What are complementary angles, and how are they different from supplementary angles?
  2. Can two obtuse angles ever be supplementary? Why or why not?
  3. How do we define alternate interior angles, and when are they equal?
  4. What is the sum of angles at a point, and how is it applied in geometry?
  5. If a transversal intersects two parallel lines, how can we use angle properties to find unknown angles?

Tip:

Always look for vertical angles or supplementary angles when working with intersecting lines, as they often provide the key to solving for unknowns.

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Math Problem Analysis

Mathematical Concepts

Algebra
Geometry
Angles

Formulas

Vertically opposite angles: angle1 = angle2
Supplementary angles: angle1 + angle2 = 180 degrees

Theorems

Vertically Opposite Angles Theorem
Supplementary Angles Theorem

Suitable Grade Level

Grades 8-10