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Finding the Fourth Proportional to 78.12, 107.85 and 56.34

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Solution

The fourth proportional to 78.12, 107.85 and 56.34 is: 77.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.12 : 107.85 = 56.34 : x
  2. Step 2: Convert to fraction form
    78.12/107.85 = 56.34/x
  3. Step 3: Cross multiply
    78.12x = 107.85 × 56.34
  4. Step 4: Simplify right side
    78.12x = 6,076.27
  5. Step 5: Solve for x
    x = 6,076.27/78.12
  6. Step 6: Final answer
    x = 77.78

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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.