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Finding the Fourth Proportional to 611.72, 843.85 and 390.44

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Solution

The fourth proportional to 611.72, 843.85 and 390.44 is: 538.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.72 : 843.85 = 390.44 : x
  2. Step 2: Convert to fraction form
    611.72/843.85 = 390.44/x
  3. Step 3: Cross multiply
    611.72x = 843.85 × 390.44
  4. Step 4: Simplify right side
    611.72x = 329,467.60
  5. Step 5: Solve for x
    x = 329,467.60/611.72
  6. Step 6: Final answer
    x = 538.60

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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.