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Finding the Fourth Proportional to 816.21, 1,223.91 and 405.27

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Solution

The fourth proportional to 816.21, 1,223.91 and 405.27 is: 607.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.21 : 1,223.91 = 405.27 : x
  2. Step 2: Convert to fraction form
    816.21/1,223.91 = 405.27/x
  3. Step 3: Cross multiply
    816.21x = 1,223.91 × 405.27
  4. Step 4: Simplify right side
    816.21x = 496,014.01
  5. Step 5: Solve for x
    x = 496,014.01/816.21
  6. Step 6: Final answer
    x = 607.70

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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.