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Finding the Fourth Proportional to 911.72, 1,258.16 and 513.40

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Solution

The fourth proportional to 911.72, 1,258.16 and 513.40 is: 708.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.72 : 1,258.16 = 513.40 : x
  2. Step 2: Convert to fraction form
    911.72/1,258.16 = 513.40/x
  3. Step 3: Cross multiply
    911.72x = 1,258.16 × 513.40
  4. Step 4: Simplify right side
    911.72x = 645,939.34
  5. Step 5: Solve for x
    x = 645,939.34/911.72
  6. Step 6: Final answer
    x = 708.48

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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.