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Finding the Fourth Proportional to 100.70, 138.98 and 71.66

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Solution

The fourth proportional to 100.70, 138.98 and 71.66 is: 98.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.70 : 138.98 = 71.66 : x
  2. Step 2: Convert to fraction form
    100.70/138.98 = 71.66/x
  3. Step 3: Cross multiply
    100.70x = 138.98 × 71.66
  4. Step 4: Simplify right side
    100.70x = 9,958.95
  5. Step 5: Solve for x
    x = 9,958.95/100.70
  6. Step 6: Final answer
    x = 98.90

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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.