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Finding the Fourth Proportional to 861.70, 1,293 and 815.23

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Solution

The fourth proportional to 861.70, 1,293 and 815.23 is: 1,223.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.70 : 1,293 = 815.23 : x
  2. Step 2: Convert to fraction form
    861.70/1,293 = 815.23/x
  3. Step 3: Cross multiply
    861.70x = 1,293 × 815.23
  4. Step 4: Simplify right side
    861.70x = 1,054,092.39
  5. Step 5: Solve for x
    x = 1,054,092.39/861.70
  6. Step 6: Final answer
    x = 1,223.27

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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.