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Finding the Fourth Proportional to 720.21, 993.94 and 405.50

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Solution

The fourth proportional to 720.21, 993.94 and 405.50 is: 559.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.21 : 993.94 = 405.50 : x
  2. Step 2: Convert to fraction form
    720.21/993.94 = 405.50/x
  3. Step 3: Cross multiply
    720.21x = 993.94 × 405.50
  4. Step 4: Simplify right side
    720.21x = 403,042.67
  5. Step 5: Solve for x
    x = 403,042.67/720.21
  6. Step 6: Final answer
    x = 559.62

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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.