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Finding the Fourth Proportional to 103.12, 142.24 and 78.48

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Solution

The fourth proportional to 103.12, 142.24 and 78.48 is: 108.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.12 : 142.24 = 78.48 : x
  2. Step 2: Convert to fraction form
    103.12/142.24 = 78.48/x
  3. Step 3: Cross multiply
    103.12x = 142.24 × 78.48
  4. Step 4: Simplify right side
    103.12x = 11,163.00
  5. Step 5: Solve for x
    x = 11,163.00/103.12
  6. Step 6: Final answer
    x = 108.25

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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.