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Finding the Fourth Proportional to 619.65, 855.01 and 398.55

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Solution

The fourth proportional to 619.65, 855.01 and 398.55 is: 549.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    619.65 : 855.01 = 398.55 : x
  2. Step 2: Convert to fraction form
    619.65/855.01 = 398.55/x
  3. Step 3: Cross multiply
    619.65x = 855.01 × 398.55
  4. Step 4: Simplify right side
    619.65x = 340,764.24
  5. Step 5: Solve for x
    x = 340,764.24/619.65
  6. Step 6: Final answer
    x = 549.93

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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.