Math Problem Statement

In the figure above, J L

7 , and the length of line segment K N is one fourth the length of line segment J N . What is the length of line segment L M ?

In the figure above, JL = 7, and the length of line segment KN is one fourth the length of line segment JN. What is the length of line segment LM?

Solution

In the given triangle, we have:

  1. JL=7JL = 7 (the length of the segment from JJ to LL),
  2. KNKN is one-fourth the length of JNJN,
  3. KLM\triangle KLM and KJN\triangle KJN are right triangles.

To find the length of LMLM, let's denote the following lengths:

  • JN=xJN = x
  • KN=14×JN=x4KN = \frac{1}{4} \times JN = \frac{x}{4}

Since KJN\triangle KJN and KLM\triangle KLM are similar triangles (due to the right angles and the shared angle KK), the ratio of corresponding sides will be the same.

Using the similarity of triangles: KNKJ=LMJL\frac{KN}{KJ} = \frac{LM}{JL}

Substitute the known values: x4x=LM7\frac{\frac{x}{4}}{x} = \frac{LM}{7}

Simplify the left side: 14=LM7\frac{1}{4} = \frac{LM}{7}

Now, solve for LMLM: LM=74LM = \frac{7}{4}

Thus, the length of segment LMLM is 74\frac{7}{4} or 1.75 units.


Would you like any further details or have any questions about this solution?

Here are 5 related questions for further practice:

  1. What is the length of JNJN?
  2. Find the area of KJN\triangle KJN.
  3. If the length of JLJL was doubled, how would that affect LMLM?
  4. What is the perimeter of KLM\triangle KLM?
  5. How would you calculate the length of segment KMKM?

Tip: When working with similar triangles, always set up a ratio between corresponding sides to find unknown lengths.

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Math Problem Analysis

Mathematical Concepts

Geometry
Similar Triangles
Proportions

Formulas

Similar Triangle Side Ratios

Theorems

Similar Triangles

Suitable Grade Level

Grades 8-10