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Finding the Fourth Proportional to 839.57, 1,258.26 and 428.36

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Solution

The fourth proportional to 839.57, 1,258.26 and 428.36 is: 641.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.57 : 1,258.26 = 428.36 : x
  2. Step 2: Convert to fraction form
    839.57/1,258.26 = 428.36/x
  3. Step 3: Cross multiply
    839.57x = 1,258.26 × 428.36
  4. Step 4: Simplify right side
    839.57x = 538,988.25
  5. Step 5: Solve for x
    x = 538,988.25/839.57
  6. Step 6: Final answer
    x = 641.98

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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.