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Finding the Fourth Proportional to 69.65, 104.28 and 42.15

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Solution

The fourth proportional to 69.65, 104.28 and 42.15 is: 63.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.65 : 104.28 = 42.15 : x
  2. Step 2: Convert to fraction form
    69.65/104.28 = 42.15/x
  3. Step 3: Cross multiply
    69.65x = 104.28 × 42.15
  4. Step 4: Simplify right side
    69.65x = 4,395.40
  5. Step 5: Solve for x
    x = 4,395.40/69.65
  6. Step 6: Final answer
    x = 63.11

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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.