Here we will prove that the line segment joining the midpoints of the nonparallel sides of a trapezium is half the sum of the lengths of the parallel sides and is also parallel to them.
Solution:
Given: PQRS is a trapezium in which PQ ∥ RS. U and V are the midpoints of QR and PS respectively.
To prove: (i) UV ∥ RS.
(ii) UV = \(\frac{1}{2}\)(PQ + RS).
Construction: Join QV and produce it to meet RS produced at T.
Proof:
Statement |
Reason |
1. In ∆PQV and ∆STV, (i) PV = VS. (ii) ∠PVQ = ∠TVS. (iii) ∠QPV = ∠VST. |
1. (i) Given. (ii) Vertically opposite angles. (iii) Alternate angles. |
2. Therefore, ∆PQV ≅ ∆STV. |
2. By ASA criterion of congruency. |
3. Therefore, PQ = ST. |
3. CPCTC. |
4. QV = VT. |
4. CPCTC. |
5. In ∆QRT, (i) U is the midpoint of QR. (ii) V is the midpoint of QT. |
5. (i) Given. (ii) From statement 4. |
6. Therefore, UV ∥ RT and UV = \(\frac{1}{2}\)RT. |
6. By the Midpoint Theorem. |
7. Therefore, UV = \(\frac{1}{2}\)(RS+ ST). |
7. From statement 6. |
8. UV = \(\frac{1}{2}\)(RS+ PQ). |
8. Using statement 3 in statement 7. |
9. Therefore, UV ∥ RS and UV = \(\frac{1}{2}\)(PQ+ RS). (Proved) |
9. From statement 6 and 8. |
From Midsegment Theorem on Trapezium 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.
Nov 25, 24 01:18 AM
Nov 25, 24 01:09 AM
Nov 25, 24 12:48 AM
Nov 25, 24 12:17 AM
Nov 24, 24 11:01 PM
New! Comments
Have your say about what you just read! Leave me a comment in the box below. Ask a Question or Answer a Question.