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Finding the Fourth Proportional to 221.99, 305.72 and 217.21

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Solution

The fourth proportional to 221.99, 305.72 and 217.21 is: 299.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.99 : 305.72 = 217.21 : x
  2. Step 2: Convert to fraction form
    221.99/305.72 = 217.21/x
  3. Step 3: Cross multiply
    221.99x = 305.72 × 217.21
  4. Step 4: Simplify right side
    221.99x = 66,405.44
  5. Step 5: Solve for x
    x = 66,405.44/221.99
  6. Step 6: Final answer
    x = 299.14

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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.