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Finding the Fourth Proportional to 318.56, 477.89 and 99.21

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Solution

The fourth proportional to 318.56, 477.89 and 99.21 is: 148.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.56 : 477.89 = 99.21 : x
  2. Step 2: Convert to fraction form
    318.56/477.89 = 99.21/x
  3. Step 3: Cross multiply
    318.56x = 477.89 × 99.21
  4. Step 4: Simplify right side
    318.56x = 47,409.69
  5. Step 5: Solve for x
    x = 47,409.69/318.56
  6. Step 6: Final answer
    x = 148.82

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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.