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Finding the Fourth Proportional to 611.79, 843.92 and 390.35

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Solution

The fourth proportional to 611.79, 843.92 and 390.35 is: 538.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.79 : 843.92 = 390.35 : x
  2. Step 2: Convert to fraction form
    611.79/843.92 = 390.35/x
  3. Step 3: Cross multiply
    611.79x = 843.92 × 390.35
  4. Step 4: Simplify right side
    611.79x = 329,425.79
  5. Step 5: Solve for x
    x = 329,425.79/611.79
  6. Step 6: Final answer
    x = 538.47

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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.