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Finding the Fourth Proportional to 219.99, 329.87 and 128.72

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Solution

The fourth proportional to 219.99, 329.87 and 128.72 is: 193.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    219.99 : 329.87 = 128.72 : x
  2. Step 2: Convert to fraction form
    219.99/329.87 = 128.72/x
  3. Step 3: Cross multiply
    219.99x = 329.87 × 128.72
  4. Step 4: Simplify right side
    219.99x = 42,458.57
  5. Step 5: Solve for x
    x = 42,458.57/219.99
  6. Step 6: Final answer
    x = 193.00

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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.