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Finding the Fourth Proportional to 78.98, 118.59 and 68.90

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Solution

The fourth proportional to 78.98, 118.59 and 68.90 is: 103.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.98 : 118.59 = 68.90 : x
  2. Step 2: Convert to fraction form
    78.98/118.59 = 68.90/x
  3. Step 3: Cross multiply
    78.98x = 118.59 × 68.90
  4. Step 4: Simplify right side
    78.98x = 8,170.85
  5. Step 5: Solve for x
    x = 8,170.85/78.98
  6. Step 6: Final answer
    x = 103.45

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.