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Finding the Fourth Proportional to 911.80, 1,257.76 and 518.75

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Solution

The fourth proportional to 911.80, 1,257.76 and 518.75 is: 715.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.80 : 1,257.76 = 518.75 : x
  2. Step 2: Convert to fraction form
    911.80/1,257.76 = 518.75/x
  3. Step 3: Cross multiply
    911.80x = 1,257.76 × 518.75
  4. Step 4: Simplify right side
    911.80x = 652,463
  5. Step 5: Solve for x
    x = 652,463/911.80
  6. Step 6: Final answer
    x = 715.58

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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.