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Finding the Fourth Proportional to 261.31, 359.78 and 221.88

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Solution

The fourth proportional to 261.31, 359.78 and 221.88 is: 305.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.31 : 359.78 = 221.88 : x
  2. Step 2: Convert to fraction form
    261.31/359.78 = 221.88/x
  3. Step 3: Cross multiply
    261.31x = 359.78 × 221.88
  4. Step 4: Simplify right side
    261.31x = 79,829.89
  5. Step 5: Solve for x
    x = 79,829.89/261.31
  6. Step 6: Final answer
    x = 305.50

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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.