If two circles of radii 18 cm and 8 cm touch externally, then the length of a direct common tangent is:

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SSC CGL 2022 Tier-I Official Paper (Held On : 12 Dec 2022 Shift 3)
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  1. 24 cm
  2. 14 cm
  3. 16 cm
  4. 12 cm

Answer (Detailed Solution Below)

Option 1 : 24 cm
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SSC CGL Tier 1 2025 Full Test - 01
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Detailed Solution

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Given:

Two circles of radii 18 cm and 8 cm touch externally

Concept used:

If two circles of radius R1 and R2 are touched externally then their direct common tangent = 2√(R1 and R2)

Calculation:

R1 = 18 cm

R2 = 8 cm

So, Direct common tangent = 2√(18 × 8)

⇒ 2√144

⇒ 2 × 12

⇒ 24 cm

∴ The length of the direct common tangent is 24 cm.

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