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Finding the Fourth Proportional to 86.50, 129.80 and 38.42

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Solution

The fourth proportional to 86.50, 129.80 and 38.42 is: 57.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.50 : 129.80 = 38.42 : x
  2. Step 2: Convert to fraction form
    86.50/129.80 = 38.42/x
  3. Step 3: Cross multiply
    86.50x = 129.80 × 38.42
  4. Step 4: Simplify right side
    86.50x = 4,986.92
  5. Step 5: Solve for x
    x = 4,986.92/86.50
  6. Step 6: Final answer
    x = 57.65

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.