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Finding the Fourth Proportional to 318.88, 478.29 and 87.78

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Solution

The fourth proportional to 318.88, 478.29 and 87.78 is: 131.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.88 : 478.29 = 87.78 : x
  2. Step 2: Convert to fraction form
    318.88/478.29 = 87.78/x
  3. Step 3: Cross multiply
    318.88x = 478.29 × 87.78
  4. Step 4: Simplify right side
    318.88x = 41,984.30
  5. Step 5: Solve for x
    x = 41,984.30/318.88
  6. Step 6: Final answer
    x = 131.66

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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.