Question

find x in each.
11.
12.
13.
14.
15.
16.
17.

• 18. draw a straight angle.

Explanation:

Step1: Use vertical angles property

Vertical angles are equal. So, \(2x + 30=130\)

Step2: Solve the equation for \(x\)

Subtract 30 from both sides: \(2x=130 - 30\), \(2x = 100\). Then divide by 2: \(x=\frac{100}{2}\)

Step1: Use supplementary angles property

Supplementary angles sum to \(180^{\circ}\). So, \(5x+35 = 180\)

Step2: Solve the equation for \(x\)

Subtract 35 from both sides: \(5x=180 - 35\), \(5x = 145\). Then divide by 5: \(x=\frac{145}{5}\)

Step1: Use right - angle property

A right - angle is \(90^{\circ}\). So, \(x + 72=90\)

Step2: Solve the equation for \(x\)

Subtract 72 from both sides: \(x=90 - 72\)

Step1: Use triangle angle - sum property

The sum of angles in a triangle is \(180^{\circ}\). So, \(8x+6x + 4x=180\)

Step2: Combine like terms and solve for \(x\)

\(18x=180\), then \(x=\frac{180}{18}\)

Answer:

\(x = 50\)