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Finding the Fourth Proportional to 611.18, 843.54 and 390.20

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Solution

The fourth proportional to 611.18, 843.54 and 390.20 is: 538.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.18 : 843.54 = 390.20 : x
  2. Step 2: Convert to fraction form
    611.18/843.54 = 390.20/x
  3. Step 3: Cross multiply
    611.18x = 843.54 × 390.20
  4. Step 4: Simplify right side
    611.18x = 329,149.31
  5. Step 5: Solve for x
    x = 329,149.31/611.18
  6. Step 6: Final answer
    x = 538.55

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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.