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Finding the Fourth Proportional to 80.48, 120.65 and 31.70

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Solution

The fourth proportional to 80.48, 120.65 and 31.70 is: 47.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.48 : 120.65 = 31.70 : x
  2. Step 2: Convert to fraction form
    80.48/120.65 = 31.70/x
  3. Step 3: Cross multiply
    80.48x = 120.65 × 31.70
  4. Step 4: Simplify right side
    80.48x = 3,824.30
  5. Step 5: Solve for x
    x = 3,824.30/80.48
  6. Step 6: Final answer
    x = 47.52

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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.