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Finding the Fourth Proportional to 83.28, 124.88 and 31.91

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Solution

The fourth proportional to 83.28, 124.88 and 31.91 is: 47.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.28 : 124.88 = 31.91 : x
  2. Step 2: Convert to fraction form
    83.28/124.88 = 31.91/x
  3. Step 3: Cross multiply
    83.28x = 124.88 × 31.91
  4. Step 4: Simplify right side
    83.28x = 3,984.14
  5. Step 5: Solve for x
    x = 3,984.14/83.28
  6. Step 6: Final answer
    x = 47.84

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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.