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Finding the Fourth Proportional to 103.30, 142.49 and 61.78

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Solution

The fourth proportional to 103.30, 142.49 and 61.78 is: 85.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.30 : 142.49 = 61.78 : x
  2. Step 2: Convert to fraction form
    103.30/142.49 = 61.78/x
  3. Step 3: Cross multiply
    103.30x = 142.49 × 61.78
  4. Step 4: Simplify right side
    103.30x = 8,803.03
  5. Step 5: Solve for x
    x = 8,803.03/103.30
  6. Step 6: Final answer
    x = 85.22

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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.