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Finding the Fourth Proportional to 720.23, 993.86 and 405.55

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Solution

The fourth proportional to 720.23, 993.86 and 405.55 is: 559.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.23 : 993.86 = 405.55 : x
  2. Step 2: Convert to fraction form
    720.23/993.86 = 405.55/x
  3. Step 3: Cross multiply
    720.23x = 993.86 × 405.55
  4. Step 4: Simplify right side
    720.23x = 403,059.92
  5. Step 5: Solve for x
    x = 403,059.92/720.23
  6. Step 6: Final answer
    x = 559.63

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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.