Four Triangles which are Congruent to One Another

Here we will show that the three line segments which join the middle points of the sides of a triangle, divide it into four triangles which are congruent to one another.

Solution:

Given: In ∆PQR, L, M and N are the midpoints of QR, RP and PQ respectively.

Four Triangles which are Congruent to One Another

To prove: ∆PMN ≅ LNM ≅ NQL ≅ MLR

Proof:

             Statement

            Reason

1. PN = \(\frac{1}{2}\)PQ.

1. N is the midpoint of PQ.

2. LM = \(\frac{1}{2}\)PQ.

2. By the Midpoint Theorem.

3. PN = LM.

3. From statement 1 and 2.

4. Similarly, PM = NL.

4. Proceeding as above.

5. In ∆PMN and ∆LNM,

(i) PN = LM

(ii) PM = NL

(iii) NM = NM.

5.

(i) From 3.

(ii) From 4.

(iv) Common side.

6. Therefore, ∆PMN ≅ LNM.

6. By SSS criterion of congruency.

7. Similarly, ∆NQL ≅ LNM.

7. Proceeding as above.

8. Also, ∆MLR ≅ LNM.

8. Proceeding as above.

9. Therefore, ∆PMN ≅ LNM ≅ NQL ≅ MLR. (Proved)

9. From statements 6, 7 and 8.





9th Grade Math

From Four Triangles which are Congruent to One Another to HOME PAGE




Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.



Share this page: What’s this?

Recent Articles

  1. Perimeter of a Square | How to Find the Perimeter of Square? |Examples

    Apr 25, 24 05:34 PM

    Perimeter of a Square
    We will discuss here how to find the perimeter of a square. Perimeter of a square is the total length (distance) of the boundary of a square. We know that all the sides of a square are equal. Perimete…

    Read More

  2. Perimeter of a Triangle | Perimeter of a Triangle Formula | Examples

    Apr 25, 24 05:13 PM

    Perimeter of a Triangle
    We will discuss here how to find the perimeter of a triangle. We know perimeter of a triangle is the total length (distance) of the boundary of a triangle. Perimeter of a triangle is the sum of length…

    Read More

  3. Perimeter of a Rectangle | How to Find the Perimeter of a Rectangle?

    Apr 25, 24 03:45 PM

    Perimeter of a Rectangle
    We will discuss here how to find the perimeter of a rectangle. We know perimeter of a rectangle is the total length (distance) of the boundary of a rectangle. ABCD is a rectangle. We know that the opp…

    Read More

  4. Dividing 3-Digit by 1-Digit Number | Long Division |Worksheet Answer

    Apr 24, 24 03:46 PM

    Dividing 3-Digit by 1-Digit Number
    Dividing 3-Digit by 1-Digit Numbers are discussed here step-by-step. How to divide 3-digit numbers by single-digit numbers? Let us follow the examples to learn to divide 3-digit number by one-digit nu…

    Read More

  5. Symmetrical Shapes | One, Two, Three, Four & Many-line Symmetry

    Apr 24, 24 03:45 PM

    Symmetrical Figures
    Symmetrical shapes are discussed here in this topic. Any object or shape which can be cut in two equal halves in such a way that both the parts are exactly the same is called symmetrical. The line whi…

    Read More