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Finding the Fourth Proportional to 421.20, 584.01 and 399.60

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Solution

The fourth proportional to 421.20, 584.01 and 399.60 is: 554.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.20 : 584.01 = 399.60 : x
  2. Step 2: Convert to fraction form
    421.20/584.01 = 399.60/x
  3. Step 3: Cross multiply
    421.20x = 584.01 × 399.60
  4. Step 4: Simplify right side
    421.20x = 233,370.40
  5. Step 5: Solve for x
    x = 233,370.40/421.20
  6. Step 6: Final answer
    x = 554.06

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.