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Finding the Fourth Proportional to 103.47, 142.78 and 56.84

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Solution

The fourth proportional to 103.47, 142.78 and 56.84 is: 78.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.47 : 142.78 = 56.84 : x
  2. Step 2: Convert to fraction form
    103.47/142.78 = 56.84/x
  3. Step 3: Cross multiply
    103.47x = 142.78 × 56.84
  4. Step 4: Simplify right side
    103.47x = 8,115.62
  5. Step 5: Solve for x
    x = 8,115.62/103.47
  6. Step 6: Final answer
    x = 78.43

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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.