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Finding the Fourth Proportional to 663.60, 993.12 and 420.24

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Solution

The fourth proportional to 663.60, 993.12 and 420.24 is: 628.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.60 : 993.12 = 420.24 : x
  2. Step 2: Convert to fraction form
    663.60/993.12 = 420.24/x
  3. Step 3: Cross multiply
    663.60x = 993.12 × 420.24
  4. Step 4: Simplify right side
    663.60x = 417,348.75
  5. Step 5: Solve for x
    x = 417,348.75/663.60
  6. Step 6: Final answer
    x = 628.92

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.