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Finding the Fourth Proportional to 71.72, 98.78 and 56.94

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Solution

The fourth proportional to 71.72, 98.78 and 56.94 is: 78.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.72 : 98.78 = 56.94 : x
  2. Step 2: Convert to fraction form
    71.72/98.78 = 56.94/x
  3. Step 3: Cross multiply
    71.72x = 98.78 × 56.94
  4. Step 4: Simplify right side
    71.72x = 5,624.53
  5. Step 5: Solve for x
    x = 5,624.53/71.72
  6. Step 6: Final answer
    x = 78.42

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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.