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Finding the Fourth Proportional to 815.56, 1,121.88 and 682.72

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Solution

The fourth proportional to 815.56, 1,121.88 and 682.72 is: 939.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.56 : 1,121.88 = 682.72 : x
  2. Step 2: Convert to fraction form
    815.56/1,121.88 = 682.72/x
  3. Step 3: Cross multiply
    815.56x = 1,121.88 × 682.72
  4. Step 4: Simplify right side
    815.56x = 765,929.91
  5. Step 5: Solve for x
    x = 765,929.91/815.56
  6. Step 6: Final answer
    x = 939.15

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.