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Finding the Fourth Proportional to 812.58, 1,218.15 and 691.62

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Solution

The fourth proportional to 812.58, 1,218.15 and 691.62 is: 1,036.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.58 : 1,218.15 = 691.62 : x
  2. Step 2: Convert to fraction form
    812.58/1,218.15 = 691.62/x
  3. Step 3: Cross multiply
    812.58x = 1,218.15 × 691.62
  4. Step 4: Simplify right side
    812.58x = 842,496.90
  5. Step 5: Solve for x
    x = 842,496.90/812.58
  6. Step 6: Final answer
    x = 1,036.82

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.