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Finding the Fourth Proportional to 103.25, 142.43 and 78.65

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Solution

The fourth proportional to 103.25, 142.43 and 78.65 is: 108.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.25 : 142.43 = 78.65 : x
  2. Step 2: Convert to fraction form
    103.25/142.43 = 78.65/x
  3. Step 3: Cross multiply
    103.25x = 142.43 × 78.65
  4. Step 4: Simplify right side
    103.25x = 11,201.01
  5. Step 5: Solve for x
    x = 11,201.01/103.25
  6. Step 6: Final answer
    x = 108.49

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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.