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Finding the Fourth Proportional to 78.18, 107.87 and 47.09

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Solution

The fourth proportional to 78.18, 107.87 and 47.09 is: 64.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.18 : 107.87 = 47.09 : x
  2. Step 2: Convert to fraction form
    78.18/107.87 = 47.09/x
  3. Step 3: Cross multiply
    78.18x = 107.87 × 47.09
  4. Step 4: Simplify right side
    78.18x = 5,079.63
  5. Step 5: Solve for x
    x = 5,079.63/78.18
  6. Step 6: Final answer
    x = 64.98

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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.