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Finding the Fourth Proportional to 261.39, 390.24 and 220.29

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Solution

The fourth proportional to 261.39, 390.24 and 220.29 is: 328.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.39 : 390.24 = 220.29 : x
  2. Step 2: Convert to fraction form
    261.39/390.24 = 220.29/x
  3. Step 3: Cross multiply
    261.39x = 390.24 × 220.29
  4. Step 4: Simplify right side
    261.39x = 85,965.97
  5. Step 5: Solve for x
    x = 85,965.97/261.39
  6. Step 6: Final answer
    x = 328.88

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.