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Finding the Fourth Proportional to 217.50, 300.17 and 128.99

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Solution

The fourth proportional to 217.50, 300.17 and 128.99 is: 178.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.50 : 300.17 = 128.99 : x
  2. Step 2: Convert to fraction form
    217.50/300.17 = 128.99/x
  3. Step 3: Cross multiply
    217.50x = 300.17 × 128.99
  4. Step 4: Simplify right side
    217.50x = 38,716.78
  5. Step 5: Solve for x
    x = 38,716.78/217.50
  6. Step 6: Final answer
    x = 178.01

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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.