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Finding the Fourth Proportional to 870.55, 1,305.91 and 221.29

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Solution

The fourth proportional to 870.55, 1,305.91 and 221.29 is: 331.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.55 : 1,305.91 = 221.29 : x
  2. Step 2: Convert to fraction form
    870.55/1,305.91 = 221.29/x
  3. Step 3: Cross multiply
    870.55x = 1,305.91 × 221.29
  4. Step 4: Simplify right side
    870.55x = 288,984.82
  5. Step 5: Solve for x
    x = 288,984.82/870.55
  6. Step 6: Final answer
    x = 331.96

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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.