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Finding the Fourth Proportional to 611.87, 843.50 and 390.65

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Solution

The fourth proportional to 611.87, 843.50 and 390.65 is: 538.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.87 : 843.50 = 390.65 : x
  2. Step 2: Convert to fraction form
    611.87/843.50 = 390.65/x
  3. Step 3: Cross multiply
    611.87x = 843.50 × 390.65
  4. Step 4: Simplify right side
    611.87x = 329,511.32
  5. Step 5: Solve for x
    x = 329,511.32/611.87
  6. Step 6: Final answer
    x = 538.53

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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.