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Finding the Fourth Proportional to 47.78, 65.94 and 31.40

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Solution

The fourth proportional to 47.78, 65.94 and 31.40 is: 43.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.78 : 65.94 = 31.40 : x
  2. Step 2: Convert to fraction form
    47.78/65.94 = 31.40/x
  3. Step 3: Cross multiply
    47.78x = 65.94 × 31.40
  4. Step 4: Simplify right side
    47.78x = 2,070.52
  5. Step 5: Solve for x
    x = 2,070.52/47.78
  6. Step 6: Final answer
    x = 43.33

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.