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Finding the Fourth Proportional to 89.72, 123.79 and 56.97

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Solution

The fourth proportional to 89.72, 123.79 and 56.97 is: 78.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.72 : 123.79 = 56.97 : x
  2. Step 2: Convert to fraction form
    89.72/123.79 = 56.97/x
  3. Step 3: Cross multiply
    89.72x = 123.79 × 56.97
  4. Step 4: Simplify right side
    89.72x = 7,052.17
  5. Step 5: Solve for x
    x = 7,052.17/89.72
  6. Step 6: Final answer
    x = 78.60

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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.