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Finding the Fourth Proportional to 500.65, 690.96 and 478.78

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Solution

The fourth proportional to 500.65, 690.96 and 478.78 is: 660.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    500.65 : 690.96 = 478.78 : x
  2. Step 2: Convert to fraction form
    500.65/690.96 = 478.78/x
  3. Step 3: Cross multiply
    500.65x = 690.96 × 478.78
  4. Step 4: Simplify right side
    500.65x = 330,817.83
  5. Step 5: Solve for x
    x = 330,817.83/500.65
  6. Step 6: Final answer
    x = 660.78

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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.