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Finding the Fourth Proportional to 47.78, 71.51 and 31.55

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Solution

The fourth proportional to 47.78, 71.51 and 31.55 is: 47.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.78 : 71.51 = 31.55 : x
  2. Step 2: Convert to fraction form
    47.78/71.51 = 31.55/x
  3. Step 3: Cross multiply
    47.78x = 71.51 × 31.55
  4. Step 4: Simplify right side
    47.78x = 2,255.63
  5. Step 5: Solve for x
    x = 2,255.63/47.78
  6. Step 6: Final answer
    x = 47.21

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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.