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Finding the Fourth Proportional to 870.18, 1,201.41 and 636.90

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Solution

The fourth proportional to 870.18, 1,201.41 and 636.90 is: 879.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.18 : 1,201.41 = 636.90 : x
  2. Step 2: Convert to fraction form
    870.18/1,201.41 = 636.90/x
  3. Step 3: Cross multiply
    870.18x = 1,201.41 × 636.90
  4. Step 4: Simplify right side
    870.18x = 765,178.03
  5. Step 5: Solve for x
    x = 765,178.03/870.18
  6. Step 6: Final answer
    x = 879.33

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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.