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Finding the Fourth Proportional to 911.70, 1,258.20 and 518.79

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Solution

The fourth proportional to 911.70, 1,258.20 and 518.79 is: 715.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.70 : 1,258.20 = 518.79 : x
  2. Step 2: Convert to fraction form
    911.70/1,258.20 = 518.79/x
  3. Step 3: Cross multiply
    911.70x = 1,258.20 × 518.79
  4. Step 4: Simplify right side
    911.70x = 652,741.58
  5. Step 5: Solve for x
    x = 652,741.58/911.70
  6. Step 6: Final answer
    x = 715.96

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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.