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Finding the Fourth Proportional to 611.40, 843.06 and 390

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Solution

The fourth proportional to 611.40, 843.06 and 390 is: 537.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.40 : 843.06 = 390 : x
  2. Step 2: Convert to fraction form
    611.40/843.06 = 390/x
  3. Step 3: Cross multiply
    611.40x = 843.06 × 390
  4. Step 4: Simplify right side
    611.40x = 328,793.40
  5. Step 5: Solve for x
    x = 328,793.40/611.40
  6. Step 6: Final answer
    x = 537.77

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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.