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Finding the Fourth Proportional to 318.88, 478.31 and 90.88

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Solution

The fourth proportional to 318.88, 478.31 and 90.88 is: 136.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.88 : 478.31 = 90.88 : x
  2. Step 2: Convert to fraction form
    318.88/478.31 = 90.88/x
  3. Step 3: Cross multiply
    318.88x = 478.31 × 90.88
  4. Step 4: Simplify right side
    318.88x = 43,466.65
  5. Step 5: Solve for x
    x = 43,466.65/318.88
  6. Step 6: Final answer
    x = 136.31

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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.