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Finding the Fourth Proportional to 89.86, 123.78 and 71.38

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Solution

The fourth proportional to 89.86, 123.78 and 71.38 is: 98.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.86 : 123.78 = 71.38 : x
  2. Step 2: Convert to fraction form
    89.86/123.78 = 71.38/x
  3. Step 3: Cross multiply
    89.86x = 123.78 × 71.38
  4. Step 4: Simplify right side
    89.86x = 8,835.44
  5. Step 5: Solve for x
    x = 8,835.44/89.86
  6. Step 6: Final answer
    x = 98.33

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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.