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Finding the Fourth Proportional to 900, 1,242 and 486

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Solution

The fourth proportional to 900, 1,242 and 486 is: 670.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    900 : 1,242 = 486 : x
  2. Step 2: Convert to fraction form
    900/1,242 = 486/x
  3. Step 3: Cross multiply
    900x = 1,242 × 486
  4. Step 4: Simplify right side
    900x = 603,612
  5. Step 5: Solve for x
    x = 603,612/900
  6. Step 6: Final answer
    x = 670.68

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.