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Finding the Fourth Proportional to 103.41, 142.78 and 78.98

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Solution

The fourth proportional to 103.41, 142.78 and 78.98 is: 109.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.41 : 142.78 = 78.98 : x
  2. Step 2: Convert to fraction form
    103.41/142.78 = 78.98/x
  3. Step 3: Cross multiply
    103.41x = 142.78 × 78.98
  4. Step 4: Simplify right side
    103.41x = 11,276.68
  5. Step 5: Solve for x
    x = 11,276.68/103.41
  6. Step 6: Final answer
    x = 109.04

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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.