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Finding the Fourth Proportional to 71.80, 107.70 and 31.25

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Solution

The fourth proportional to 71.80, 107.70 and 31.25 is: 46.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.80 : 107.70 = 31.25 : x
  2. Step 2: Convert to fraction form
    71.80/107.70 = 31.25/x
  3. Step 3: Cross multiply
    71.80x = 107.70 × 31.25
  4. Step 4: Simplify right side
    71.80x = 3,366.04
  5. Step 5: Solve for x
    x = 3,366.04/71.80
  6. Step 6: Final answer
    x = 46.88

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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.