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Finding the Fourth Proportional to 318.60, 439.20 and 306

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Solution

The fourth proportional to 318.60, 439.20 and 306 is: 421.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.60 : 439.20 = 306 : x
  2. Step 2: Convert to fraction form
    318.60/439.20 = 306/x
  3. Step 3: Cross multiply
    318.60x = 439.20 × 306
  4. Step 4: Simplify right side
    318.60x = 134,395.20
  5. Step 5: Solve for x
    x = 134,395.20/318.60
  6. Step 6: Final answer
    x = 421.83

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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.