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Finding the Fourth Proportional to 478.58, 660.15 and 312.80

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Solution

The fourth proportional to 478.58, 660.15 and 312.80 is: 431.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.58 : 660.15 = 312.80 : x
  2. Step 2: Convert to fraction form
    478.58/660.15 = 312.80/x
  3. Step 3: Cross multiply
    478.58x = 660.15 × 312.80
  4. Step 4: Simplify right side
    478.58x = 206,491.62
  5. Step 5: Solve for x
    x = 206,491.62/478.58
  6. Step 6: Final answer
    x = 431.47

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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.