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Finding the Fourth Proportional to 84.10, 115.80 and 71.80

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Solution

The fourth proportional to 84.10, 115.80 and 71.80 is: 98.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.10 : 115.80 = 71.80 : x
  2. Step 2: Convert to fraction form
    84.10/115.80 = 71.80/x
  3. Step 3: Cross multiply
    84.10x = 115.80 × 71.80
  4. Step 4: Simplify right side
    84.10x = 8,314.44
  5. Step 5: Solve for x
    x = 8,314.44/84.10
  6. Step 6: Final answer
    x = 98.86

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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.