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Finding the Fourth Proportional to 813.63, 1,122.84 and 636.78

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Solution

The fourth proportional to 813.63, 1,122.84 and 636.78 is: 878.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.63 : 1,122.84 = 636.78 : x
  2. Step 2: Convert to fraction form
    813.63/1,122.84 = 636.78/x
  3. Step 3: Cross multiply
    813.63x = 1,122.84 × 636.78
  4. Step 4: Simplify right side
    813.63x = 715,002.06
  5. Step 5: Solve for x
    x = 715,002.06/813.63
  6. Step 6: Final answer
    x = 878.78

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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.