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Finding the Fourth Proportional to 47.92, 71.28 and 47.40

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Solution

The fourth proportional to 47.92, 71.28 and 47.40 is: 70.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.92 : 71.28 = 47.40 : x
  2. Step 2: Convert to fraction form
    47.92/71.28 = 47.40/x
  3. Step 3: Cross multiply
    47.92x = 71.28 × 47.40
  4. Step 4: Simplify right side
    47.92x = 3,378.67
  5. Step 5: Solve for x
    x = 3,378.67/47.92
  6. Step 6: Final answer
    x = 70.51

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.