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Finding the Fourth Proportional to 870.45, 1,305.68 and 221.19

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Solution

The fourth proportional to 870.45, 1,305.68 and 221.19 is: 331.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.45 : 1,305.68 = 221.19 : x
  2. Step 2: Convert to fraction form
    870.45/1,305.68 = 221.19/x
  3. Step 3: Cross multiply
    870.45x = 1,305.68 × 221.19
  4. Step 4: Simplify right side
    870.45x = 288,796.83
  5. Step 5: Solve for x
    x = 288,796.83/870.45
  6. Step 6: Final answer
    x = 331.78

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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.