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Finding the Fourth Proportional to 318.63, 477.81 and 99.20

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Solution

The fourth proportional to 318.63, 477.81 and 99.20 is: 148.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.63 : 477.81 = 99.20 : x
  2. Step 2: Convert to fraction form
    318.63/477.81 = 99.20/x
  3. Step 3: Cross multiply
    318.63x = 477.81 × 99.20
  4. Step 4: Simplify right side
    318.63x = 47,395.87
  5. Step 5: Solve for x
    x = 47,395.87/318.63
  6. Step 6: Final answer
    x = 148.75

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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.