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Finding the Fourth Proportional to 83.70, 115.50 and 71.40

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Solution

The fourth proportional to 83.70, 115.50 and 71.40 is: 98.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.70 : 115.50 = 71.40 : x
  2. Step 2: Convert to fraction form
    83.70/115.50 = 71.40/x
  3. Step 3: Cross multiply
    83.70x = 115.50 × 71.40
  4. Step 4: Simplify right side
    83.70x = 8,246.70
  5. Step 5: Solve for x
    x = 8,246.70/83.70
  6. Step 6: Final answer
    x = 98.53

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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.