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Finding the Fourth Proportional to 870.47, 1,305.71 and 221.21

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Solution

The fourth proportional to 870.47, 1,305.71 and 221.21 is: 331.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.47 : 1,305.71 = 221.21 : x
  2. Step 2: Convert to fraction form
    870.47/1,305.71 = 221.21/x
  3. Step 3: Cross multiply
    870.47x = 1,305.71 × 221.21
  4. Step 4: Simplify right side
    870.47x = 288,828.47
  5. Step 5: Solve for x
    x = 288,828.47/870.47
  6. Step 6: Final answer
    x = 331.81

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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.