What is Thales Theorem Explain with proof
Answers
Answer:
In geometry, Thales's theorem states that if A, B, and C are distinct points on a circle where the line AC is a diameter, the angle ABC is a right angle. Thales's theorem is a special case of the inscribed angle theorem and is mentioned and proved as part of the 31st proposition in the third book of Euclid's Elements.
Step-by-step explanation:
If a line is drawn parallel to one side of a triangle intersecting the other two sides in distinct points, then the other two sides are divided in the same ratio.
Now the area of ∆APQ = 1/2 × AP × QN (Since, area of a triangle= 1/2× Base × Height)
Similarly, area of ∆PBQ= 1/2 × PB × QN
area of ∆APQ = 1/2 × AQ × PM
Also,area of ∆QCP = 1/2 × QC × PM ………… (1)
Now, if we find the ratio of the area of triangles ∆APQand ∆PBQ, we have
area of ΔAPQarea of ΔPBQ = 12 × AP × QN12 × PB × QN = APPB
Similarly, area of ΔAPQarea of ΔQCP = 12 × AQ × PM12 × QC × PM = AQQC ………..(2)
According to the property of triangles, the triangles drawn between the same parallel lines and on the same base have equal areas.
Therefore, we can say that ∆PBQ and QCP have the same area.
area of ∆PBQ = area of ∆QCP …………..(3)
Therefore, from the equations (1), (2) and (3) we can say that,
AP/PB = AQ/QC