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Finding the Fourth Proportional to 869.92, 1,302.38 and 815.42

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Solution

The fourth proportional to 869.92, 1,302.38 and 815.42 is: 1,220.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.92 : 1,302.38 = 815.42 : x
  2. Step 2: Convert to fraction form
    869.92/1,302.38 = 815.42/x
  3. Step 3: Cross multiply
    869.92x = 1,302.38 × 815.42
  4. Step 4: Simplify right side
    869.92x = 1,061,986.70
  5. Step 5: Solve for x
    x = 1,061,986.70/869.92
  6. Step 6: Final answer
    x = 1,220.79

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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.