In the diagram,<LMN=<ONM=90.P is the midpoint of MN.MN=2ML and MN=NO.prove that <OPN=<LNO
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To prove that <OPN = <LNO, we can use the fact that P is the midpoint of MN and MN = NO.
Given:
∠LMN = ∠ONM = 90°
P is the midpoint of MN
MN = 2ML
MN = NO
To prove:
∠OPN = ∠LNO
Proof:
1. Triangles LNO and PON are right triangles (since ∠LMN = ∠ONM = 90°).
2. By the definition of a right triangle, ∠NPO = ∠ONL and ∠NOP = ∠LON.
3. Since P is the midpoint of MN, NP = MP.
4. From the given information, MN = NO.
5. By the definition of a midpoint, MN = 2ML.
6. Combining the above equations, 2ML = NO.
7. Since NP = MP and NO = 2ML, triangle NOP is congruent to triangle LNP by the Side-Angle-Side (SAS) congruence criterion.
8. By the congruence of triangles NOP and LNP, ∠OPN = ∠LNO.
Therefore, <OPN = <LNO.
To prove that ∠OPN = ∠LNO, we can use the properties of isosceles triangles and parallel lines.
Here are the steps to prove this statement:
Step 1: Given information
- <LMN = <ONM = 90° (Right angles)
- P is the midpoint of MN (PN = PM)
- MN = 2ML (Two times the length of ML)
- MN = NO (The sides MN and NO are equal)
Step 2: Drawing additional lines
- Extend ML to point Q such that LQ = LP. Now, we have two congruent segments PQ and PL.
- Draw line OQ.
Step 3: Identifying congruent triangles
- In triangle MPL and triangle NPL, we have MP = NP (P is the midpoint of MN) and PL = PL (common side). Additionally, angle MPL = angle NPL = 90° (given).
- Therefore, triangle MPL and triangle NPL are congruent by the hypotenuse-leg congruence theorem.
Step 4: Proving parallel lines
- Since triangle MPL and triangle NPL are congruent, the corresponding angles are congruent as well.
- Therefore, angle LNO = angle LNP (corresponding angles of congruent triangles).
Step 5: Proving isosceles triangles
- In triangle LQN, we have LQ = LP (constructed line) and angle LNO = angle LNP (proved in the previous step).
- Therefore, triangle LNO is an isosceles triangle.
Step 6: Proving congruent base angles
- In an isosceles triangle, the base angles are congruent.
- Hence, angle OPN = angle LNO (congruent base angles of isosceles triangle LNO).
Therefore, we have proved that ∠OPN = ∠LNO.