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Finding the Fourth Proportional to 917.12, 1,265.91 and 618.80

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Solution

The fourth proportional to 917.12, 1,265.91 and 618.80 is: 854.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    917.12 : 1,265.91 = 618.80 : x
  2. Step 2: Convert to fraction form
    917.12/1,265.91 = 618.80/x
  3. Step 3: Cross multiply
    917.12x = 1,265.91 × 618.80
  4. Step 4: Simplify right side
    917.12x = 783,335.68
  5. Step 5: Solve for x
    x = 783,335.68/917.12
  6. Step 6: Final answer
    x = 854.13

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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.