Math Problem Statement

9. If m∠LKM = 7x − 5 and m∠NKM = 3x + 9, find m∠LKM. 10. If m∠NKL = 7x − 9 and m∠JKM = x + 3, find m∠JKN.

Solution

Let's solve the problems step by step.

Problem 9:

We are given:

  • mLKM=7x5m \angle LKM = 7x - 5
  • mNKM=3x+9m \angle NKM = 3x + 9

We know that KN\overrightarrow{KN} bisects LKM\angle LKM, which means: mLKN=mNKMm \angle LKN = m \angle NKM

Since mLKMm \angle LKM is the entire angle and KN\overrightarrow{KN} bisects it, we have: mLKN=mNKM=mLKM2m \angle LKN = m \angle NKM = \frac{m \angle LKM}{2}

Substituting the values: 3x+9=7x523x + 9 = \frac{7x - 5}{2}

Now, solve for xx: 2(3x+9)=7x52(3x + 9) = 7x - 5 6x+18=7x56x + 18 = 7x - 5 18+5=7x6x18 + 5 = 7x - 6x x=23x = 23

Now, substitute x=23x = 23 back into the expression for mLKMm \angle LKM: mLKM=7(23)5=1615=156m \angle LKM = 7(23) - 5 = 161 - 5 = 156^\circ

Answer for Problem 9:

mLKM=156m \angle LKM = 156^\circ


Problem 10:

We are given:

  • mNKL=7x9m \angle NKL = 7x - 9
  • mJKM=x+3m \angle JKM = x + 3

Since KJ\overrightarrow{KJ} and KL\overrightarrow{KL} are opposite rays, NKL+JKM=180\angle NKL + \angle JKM = 180^\circ.

Therefore: (7x9)+(x+3)=180(7x - 9) + (x + 3) = 180 8x6=1808x - 6 = 180 8x=1868x = 186 x=23.25x = 23.25

Now, substitute x=23.25x = 23.25 back into the expression for mJKNm \angle JKN (which is mJKMm \angle JKM since the ray KN\overrightarrow{KN} is the bisector): mJKN=23.25+3=26.25m \angle JKN = 23.25 + 3 = 26.25^\circ

Answer for Problem 10:

mJKN=26.25m \angle JKN = 26.25^\circ


Would you like more details on these steps or do you have any questions?

Here are 5 related questions you might be interested in:

  1. How do you determine if two rays are opposite?
  2. What is the significance of an angle bisector in geometry?
  3. How do you find the value of an unknown angle in a triangle?
  4. Can you explain why the sum of opposite rays' angles is always 180°?
  5. How would you solve if the given angles involved different variables?

Tip: When dealing with equations involving angle bisectors, always set up your equations based on the property that the bisector divides the angle into two equal parts.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Angle Bisectors
Linear Pair
Algebra
Equations

Formulas

m∠LKN = m∠NKM = (m∠LKM)/2
m∠NKL + m∠JKM = 180°

Theorems

Angle Bisector Theorem
Linear Pair Postulate

Suitable Grade Level

Grade 8-10