Lab Manual - To verify the Basic Proportionality Theorem
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Answers
Hey!
BPT (Basic Proportionality Theorem) is also known as Thales Theorem.
-prefer attachment
So,
ar(BDE)=ar(DEC)
Therefore, from eq. (i),(ii) and (iii)
We have,
AD/DB = AE/EC
Hence Proved.
Answer:
Basic Proportionality Theorem
If a line is drawn parallel to one side of a triangle, to intersect the other two sides at distinct points, the other two sides are divided in the same ratio.
Prerequisite Knowledge
- Statement of Basic Proportionality theorem.
- Drawing a line parallel to a given line which passes through a given point.
Materials Required
White chart paper, coloured papers, geometry box, sketch pens, fevicol, a pair of scissors, ruled paper sheet (or Parallel line board).
Procedure
- Cut an acute-angled triangle say ABC from a coloured paper. [See the image]
- Paste the ΔABC on ruled sheet such that the base of the triangle coincides with ruled line. [see the image]
- Mark two points P and Q on AB and AC such that PQ || BC.
- Using a ruler measure the length of AP, PB, AQ and QC.
- Repeat the same for right-angled triangle and obtuse-angled triangle.
- Now complete the following observation table.
Observation
[See the image]
Result
In each set of triangles, we verified that \frac { AP }{ PB } =\frac { AQ }{ QC }
Learning Outcome
Students will observe that in all the three triangles the Basic Proportionality theorem is verified.