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Finding the Fourth Proportional to 405, 558.90 and 221

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Solution

The fourth proportional to 405, 558.90 and 221 is: 304.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    405 : 558.90 = 221 : x
  2. Step 2: Convert to fraction form
    405/558.90 = 221/x
  3. Step 3: Cross multiply
    405x = 558.90 × 221
  4. Step 4: Simplify right side
    405x = 123,516.90
  5. Step 5: Solve for x
    x = 123,516.90/405
  6. Step 6: Final answer
    x = 304.98

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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.