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Finding the Fourth Proportional to 911.55, 1,257.95 and 518.58

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Solution

The fourth proportional to 911.55, 1,257.95 and 518.58 is: 715.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.55 : 1,257.95 = 518.58 : x
  2. Step 2: Convert to fraction form
    911.55/1,257.95 = 518.58/x
  3. Step 3: Cross multiply
    911.55x = 1,257.95 × 518.58
  4. Step 4: Simplify right side
    911.55x = 652,345.12
  5. Step 5: Solve for x
    x = 652,345.12/911.55
  6. Step 6: Final answer
    x = 715.64

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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.