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Finding the Fourth Proportional to 911.48, 1,257.87 and 513.20

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Solution

The fourth proportional to 911.48, 1,257.87 and 513.20 is: 708.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.48 : 1,257.87 = 513.20 : x
  2. Step 2: Convert to fraction form
    911.48/1,257.87 = 513.20/x
  3. Step 3: Cross multiply
    911.48x = 1,257.87 × 513.20
  4. Step 4: Simplify right side
    911.48x = 645,538.88
  5. Step 5: Solve for x
    x = 645,538.88/911.48
  6. Step 6: Final answer
    x = 708.23

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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.