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Finding the Fourth Proportional to 815.37, 1,123.88 and 638.02

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Solution

The fourth proportional to 815.37, 1,123.88 and 638.02 is: 879.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.37 : 1,123.88 = 638.02 : x
  2. Step 2: Convert to fraction form
    815.37/1,123.88 = 638.02/x
  3. Step 3: Cross multiply
    815.37x = 1,123.88 × 638.02
  4. Step 4: Simplify right side
    815.37x = 717,057.92
  5. Step 5: Solve for x
    x = 717,057.92/815.37
  6. Step 6: Final answer
    x = 879.43

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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.