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Finding the Fourth Proportional to 78.50, 108.35 and 49.42

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Solution

The fourth proportional to 78.50, 108.35 and 49.42 is: 68.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.50 : 108.35 = 49.42 : x
  2. Step 2: Convert to fraction form
    78.50/108.35 = 49.42/x
  3. Step 3: Cross multiply
    78.50x = 108.35 × 49.42
  4. Step 4: Simplify right side
    78.50x = 5,353.87
  5. Step 5: Solve for x
    x = 5,353.87/78.50
  6. Step 6: Final answer
    x = 68.20

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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.