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Finding the Fourth Proportional to 816.90, 1,223.81 and 405.82

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Solution

The fourth proportional to 816.90, 1,223.81 and 405.82 is: 607.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.90 : 1,223.81 = 405.82 : x
  2. Step 2: Convert to fraction form
    816.90/1,223.81 = 405.82/x
  3. Step 3: Cross multiply
    816.90x = 1,223.81 × 405.82
  4. Step 4: Simplify right side
    816.90x = 496,646.57
  5. Step 5: Solve for x
    x = 496,646.57/816.90
  6. Step 6: Final answer
    x = 607.96

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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.