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Finding the Fourth Proportional to 105.98, 146.21 and 78.30

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Solution

The fourth proportional to 105.98, 146.21 and 78.30 is: 108.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.98 : 146.21 = 78.30 : x
  2. Step 2: Convert to fraction form
    105.98/146.21 = 78.30/x
  3. Step 3: Cross multiply
    105.98x = 146.21 × 78.30
  4. Step 4: Simplify right side
    105.98x = 11,447.85
  5. Step 5: Solve for x
    x = 11,447.85/105.98
  6. Step 6: Final answer
    x = 108.02

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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.