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Finding the Fourth Proportional to 911.07, 1,257.21 and 518.09

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Solution

The fourth proportional to 911.07, 1,257.21 and 518.09 is: 714.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.07 : 1,257.21 = 518.09 : x
  2. Step 2: Convert to fraction form
    911.07/1,257.21 = 518.09/x
  3. Step 3: Cross multiply
    911.07x = 1,257.21 × 518.09
  4. Step 4: Simplify right side
    911.07x = 651,341.64
  5. Step 5: Solve for x
    x = 651,341.64/911.07
  6. Step 6: Final answer
    x = 714.92

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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.