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Finding the Fourth Proportional to 318.40, 439.05 and 220.21

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Solution

The fourth proportional to 318.40, 439.05 and 220.21 is: 303.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.40 : 439.05 = 220.21 : x
  2. Step 2: Convert to fraction form
    318.40/439.05 = 220.21/x
  3. Step 3: Cross multiply
    318.40x = 439.05 × 220.21
  4. Step 4: Simplify right side
    318.40x = 96,683.20
  5. Step 5: Solve for x
    x = 96,683.20/318.40
  6. Step 6: Final answer
    x = 303.65

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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.