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Finding the Fourth Proportional to 665.15, 998.19 and 391.41

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Solution

The fourth proportional to 665.15, 998.19 and 391.41 is: 587.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.15 : 998.19 = 391.41 : x
  2. Step 2: Convert to fraction form
    665.15/998.19 = 391.41/x
  3. Step 3: Cross multiply
    665.15x = 998.19 × 391.41
  4. Step 4: Simplify right side
    665.15x = 390,701.55
  5. Step 5: Solve for x
    x = 390,701.55/665.15
  6. Step 6: Final answer
    x = 587.39

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.