Find x. (4x + 10) 40°

Elementary Geometry For College Students, 7e
7th Edition
ISBN:9781337614085
Author:Alexander, Daniel C.; Koeberlein, Geralyn M.
Publisher:Alexander, Daniel C.; Koeberlein, Geralyn M.
ChapterP: Preliminary Concepts
SectionP.CT: Test
Problem 1CT
icon
Related questions
Question
**Find x.**

The image shows an isosceles triangle with one of the base angles labeled as \(40^\circ\). The apex angle, indicated with an expression, is \( (4x + 10)^\circ \).

### Explanation:

In an isosceles triangle, two sides are equal, and the angles opposite those sides are also equal.

Given:
- The base angles of the triangle are equal. Since one base angle is \(40^\circ\), the other base angle is also \(40^\circ\).
- The sum of the angles in any triangle is \(180^\circ\).

Thus, we can write the equation:

\[
40 + 40 + (4x + 10) = 180
\]

Simplify and solve for \(x\):

1. Combine the known angles:
   \[
   80 + (4x + 10) = 180
   \]

2. Combine like terms:
   \[
   4x + 90 = 180
   \]

3. Subtract 90 from both sides:
   \[
   4x = 90
   \]

4. Divide both sides by 4:
   \[
   x = 22.5
   \]

**Answer: \(x = 22.5\)**
Transcribed Image Text:**Find x.** The image shows an isosceles triangle with one of the base angles labeled as \(40^\circ\). The apex angle, indicated with an expression, is \( (4x + 10)^\circ \). ### Explanation: In an isosceles triangle, two sides are equal, and the angles opposite those sides are also equal. Given: - The base angles of the triangle are equal. Since one base angle is \(40^\circ\), the other base angle is also \(40^\circ\). - The sum of the angles in any triangle is \(180^\circ\). Thus, we can write the equation: \[ 40 + 40 + (4x + 10) = 180 \] Simplify and solve for \(x\): 1. Combine the known angles: \[ 80 + (4x + 10) = 180 \] 2. Combine like terms: \[ 4x + 90 = 180 \] 3. Subtract 90 from both sides: \[ 4x = 90 \] 4. Divide both sides by 4: \[ x = 22.5 \] **Answer: \(x = 22.5\)**
Expert Solution
steps

Step by step

Solved in 2 steps with 1 images

Blurred answer