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Finding the Fourth Proportional to 318.99, 439.99 and 308.28

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Solution

The fourth proportional to 318.99, 439.99 and 308.28 is: 425.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.99 : 439.99 = 308.28 : x
  2. Step 2: Convert to fraction form
    318.99/439.99 = 308.28/x
  3. Step 3: Cross multiply
    318.99x = 439.99 × 308.28
  4. Step 4: Simplify right side
    318.99x = 135,640.26
  5. Step 5: Solve for x
    x = 135,640.26/318.99
  6. Step 6: Final answer
    x = 425.21

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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.