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Δ ABC ~ Δ PQR. A(Δ ABC) = 80 cm2, A(Δ PQR) = 125 cm2 and AB = 12 cm. Complete the following activity to find PQ.Solution :Δ ABC ~ Δ PQR .................... (given)\(\therefore \dfrac{A(\Delta ABC)}{A(\Delta PQR)} = \dfrac{\text{____}}{PQ^2}\) ......…

Q.3 (A)(1) Δ ABC ~ Δ PQR. A(Δ ABC) = 80 cm2, A(Δ PQR) = 125 cm2 and AB = 12 cm. Complete the following activity to find PQ.

Solution :

Δ ABC ~ Δ PQR .................... (given)
\(\therefore \dfrac{A(\Delta ABC)}{A(\Delta PQR)} = \dfrac{\text{____}}{PQ^2}\) .................... (theorem of areas of similar triangles)
\(\therefore \dfrac{80}{125} = \dfrac{12^2}{PQ^2}\)
\(\therefore \dfrac{16}{25} = \dfrac{12^2}{PQ^2}\)
\(\therefore \dfrac{\text{____}}{5} = \dfrac{12}{PQ}\) .................... (taking square roots)
\(\therefore PQ =\) ____ cm

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Best answer

Answer: PQ = 15 cm

Δ ABC ~ Δ PQR, so \(\dfrac{A(\Delta ABC)}{A(\Delta PQR)} = \dfrac{AB^2}{PQ^2}\) (theorem of areas of similar triangles).

\(\dfrac{80}{125} = \dfrac{16}{25} = \dfrac{12^2}{PQ^2}\).

Taking square roots: \(\dfrac{4}{5} = \dfrac{12}{PQ} \Rightarrow PQ = \dfrac{12 \times 5}{4} = 15\) cm.

Blanks in order: \(AB^2\), 4, 15.

Doubtly AI · 27 Oct 2026 AI-generated · not yet verified Report
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