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Finding the Fourth Proportional to 911.06, 1,257.31 and 518.21

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Solution

The fourth proportional to 911.06, 1,257.31 and 518.21 is: 715.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.06 : 1,257.31 = 518.21 : x
  2. Step 2: Convert to fraction form
    911.06/1,257.31 = 518.21/x
  3. Step 3: Cross multiply
    911.06x = 1,257.31 × 518.21
  4. Step 4: Simplify right side
    911.06x = 651,549.69
  5. Step 5: Solve for x
    x = 651,549.69/911.06
  6. Step 6: Final answer
    x = 715.16

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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.