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Finding the Fourth Proportional to 613.55, 920.21 and 393.86

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Solution

The fourth proportional to 613.55, 920.21 and 393.86 is: 590.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    613.55 : 920.21 = 393.86 : x
  2. Step 2: Convert to fraction form
    613.55/920.21 = 393.86/x
  3. Step 3: Cross multiply
    613.55x = 920.21 × 393.86
  4. Step 4: Simplify right side
    613.55x = 362,434.24
  5. Step 5: Solve for x
    x = 362,434.24/613.55
  6. Step 6: Final answer
    x = 590.71

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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.