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Finding the Fourth Proportional to 911.60, 1,257.72 and 810.80

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Solution

The fourth proportional to 911.60, 1,257.72 and 810.80 is: 1,118.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.60 : 1,257.72 = 810.80 : x
  2. Step 2: Convert to fraction form
    911.60/1,257.72 = 810.80/x
  3. Step 3: Cross multiply
    911.60x = 1,257.72 × 810.80
  4. Step 4: Simplify right side
    911.60x = 1,019,759.38
  5. Step 5: Solve for x
    x = 1,019,759.38/911.60
  6. Step 6: Final answer
    x = 1,118.65

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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.