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Finding the Fourth Proportional to 816.58, 1,223.40 and 687.39

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Solution

The fourth proportional to 816.58, 1,223.40 and 687.39 is: 1,029.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    816.58 : 1,223.40 = 687.39 : x
  2. Step 2: Convert to fraction form
    816.58/1,223.40 = 687.39/x
  3. Step 3: Cross multiply
    816.58x = 1,223.40 × 687.39
  4. Step 4: Simplify right side
    816.58x = 840,952.93
  5. Step 5: Solve for x
    x = 840,952.93/816.58
  6. Step 6: Final answer
    x = 1,029.85

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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.