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Finding the Fourth Proportional to 287.90, 397.33 and 221.58

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Solution

The fourth proportional to 287.90, 397.33 and 221.58 is: 305.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    287.90 : 397.33 = 221.58 : x
  2. Step 2: Convert to fraction form
    287.90/397.33 = 221.58/x
  3. Step 3: Cross multiply
    287.90x = 397.33 × 221.58
  4. Step 4: Simplify right side
    287.90x = 88,040.38
  5. Step 5: Solve for x
    x = 88,040.38/287.90
  6. Step 6: Final answer
    x = 305.80

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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.