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Finding the Fourth Proportional to 312.84, 469.31 and 81.77

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Solution

The fourth proportional to 312.84, 469.31 and 81.77 is: 122.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.84 : 469.31 = 81.77 : x
  2. Step 2: Convert to fraction form
    312.84/469.31 = 81.77/x
  3. Step 3: Cross multiply
    312.84x = 469.31 × 81.77
  4. Step 4: Simplify right side
    312.84x = 38,372.72
  5. Step 5: Solve for x
    x = 38,372.72/312.84
  6. Step 6: Final answer
    x = 122.66

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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.