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Finding the Fourth Proportional to 478.50, 660.51 and 312.86

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Solution

The fourth proportional to 478.50, 660.51 and 312.86 is: 431.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.50 : 660.51 = 312.86 : x
  2. Step 2: Convert to fraction form
    478.50/660.51 = 312.86/x
  3. Step 3: Cross multiply
    478.50x = 660.51 × 312.86
  4. Step 4: Simplify right side
    478.50x = 206,643.86
  5. Step 5: Solve for x
    x = 206,643.86/478.50
  6. Step 6: Final answer
    x = 431.86

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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.