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Finding the Fourth Proportional to 813.05, 1,218.70 and 422.66

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Solution

The fourth proportional to 813.05, 1,218.70 and 422.66 is: 633.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.05 : 1,218.70 = 422.66 : x
  2. Step 2: Convert to fraction form
    813.05/1,218.70 = 422.66/x
  3. Step 3: Cross multiply
    813.05x = 1,218.70 × 422.66
  4. Step 4: Simplify right side
    813.05x = 515,095.74
  5. Step 5: Solve for x
    x = 515,095.74/813.05
  6. Step 6: Final answer
    x = 633.54

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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.