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Finding the Fourth Proportional to 611.57, 843.56 and 390.80

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Solution

The fourth proportional to 611.57, 843.56 and 390.80 is: 539.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.57 : 843.56 = 390.80 : x
  2. Step 2: Convert to fraction form
    611.57/843.56 = 390.80/x
  3. Step 3: Cross multiply
    611.57x = 843.56 × 390.80
  4. Step 4: Simplify right side
    611.57x = 329,657.08
  5. Step 5: Solve for x
    x = 329,657.08/611.57
  6. Step 6: Final answer
    x = 539.04

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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.