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Finding the Fourth Proportional to 219.99, 330 and 128.79

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Solution

The fourth proportional to 219.99, 330 and 128.79 is: 193.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    219.99 : 330 = 128.79 : x
  2. Step 2: Convert to fraction form
    219.99/330 = 128.79/x
  3. Step 3: Cross multiply
    219.99x = 330 × 128.79
  4. Step 4: Simplify right side
    219.99x = 42,500.70
  5. Step 5: Solve for x
    x = 42,500.70/219.99
  6. Step 6: Final answer
    x = 193.19

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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.