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Finding the Fourth Proportional to 89.81, 123.80 and 71.38

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Solution

The fourth proportional to 89.81, 123.80 and 71.38 is: 98.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.81 : 123.80 = 71.38 : x
  2. Step 2: Convert to fraction form
    89.81/123.80 = 71.38/x
  3. Step 3: Cross multiply
    89.81x = 123.80 × 71.38
  4. Step 4: Simplify right side
    89.81x = 8,836.64
  5. Step 5: Solve for x
    x = 8,836.64/89.81
  6. Step 6: Final answer
    x = 98.39

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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.