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Finding the Fourth Proportional to 285.31, 427.94 and 79.86

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Solution

The fourth proportional to 285.31, 427.94 and 79.86 is: 119.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.31 : 427.94 = 79.86 : x
  2. Step 2: Convert to fraction form
    285.31/427.94 = 79.86/x
  3. Step 3: Cross multiply
    285.31x = 427.94 × 79.86
  4. Step 4: Simplify right side
    285.31x = 34,175.29
  5. Step 5: Solve for x
    x = 34,175.29/285.31
  6. Step 6: Final answer
    x = 119.78

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.