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Finding the Fourth Proportional to 870.47, 1,305.70 and 221.25

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Solution

The fourth proportional to 870.47, 1,305.70 and 221.25 is: 331.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.47 : 1,305.70 = 221.25 : x
  2. Step 2: Convert to fraction form
    870.47/1,305.70 = 221.25/x
  3. Step 3: Cross multiply
    870.47x = 1,305.70 × 221.25
  4. Step 4: Simplify right side
    870.47x = 288,886.13
  5. Step 5: Solve for x
    x = 288,886.13/870.47
  6. Step 6: Final answer
    x = 331.87

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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.