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Mathematics

In the given figure ∠BAP = ∠DCP = 70°, PC = 6 cm and CA = 4 cm, then PD : DB is :

  1. 5 : 3

  2. 3 : 5

  3. 3 : 2

  4. 2 : 3

In the given figure ∠BAP = ∠DCP = 70°, PC = 6 cm and CA = 4 cm, then PD : DB is : ICSE 2023 Maths Solved Question Paper.

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ICSE 2023

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Answer

Given,

∠BAP = ∠DCP = 70°

From figure,

∠BAP and ∠DCP are corresponding angles and since they are equal.

∴ AB // CD.

From figure,

PA = PC + AC = 6 + 4 = 10 cm.

In △ PAB and △ PCD,

⇒ ∠PAB = ∠PCD (Both equal to 70°)

⇒ ∠BPA = ∠DPC (Both are equal)

∴ △ PAB ~ △ PCD (By A.A. axiom)

We know that,

Corresponding sides of similar triangle are proportional to each other.

PBPD=PAPCPBPD=106PBPD=53.\Rightarrow \dfrac{PB}{PD} = \dfrac{PA}{PC} \\[1em] \Rightarrow \dfrac{PB}{PD} = \dfrac{10}{6} \\[1em] \Rightarrow \dfrac{PB}{PD} = \dfrac{5}{3}.

Let PB = 5x and PD = 3x.

From figure,

DB = PB - PD = 5x - 3x = 2x.

PDDB=3x2x=32\Rightarrow \dfrac{PD}{DB} = \dfrac{3x}{2x} = \dfrac{3}{2}

⇒ PD : DB = 3 : 2.

Hence, Option 3 is the correct option.

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