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Finding the Fourth Proportional to 78.57, 108.21 and 75.42

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Solution

The fourth proportional to 78.57, 108.21 and 75.42 is: 103.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.57 : 108.21 = 75.42 : x
  2. Step 2: Convert to fraction form
    78.57/108.21 = 75.42/x
  3. Step 3: Cross multiply
    78.57x = 108.21 × 75.42
  4. Step 4: Simplify right side
    78.57x = 8,161.20
  5. Step 5: Solve for x
    x = 8,161.20/78.57
  6. Step 6: Final answer
    x = 103.87

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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.