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Finding the Fourth Proportional to 222.45, 306.99 and 129.21

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Solution

The fourth proportional to 222.45, 306.99 and 129.21 is: 178.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    222.45 : 306.99 = 129.21 : x
  2. Step 2: Convert to fraction form
    222.45/306.99 = 129.21/x
  3. Step 3: Cross multiply
    222.45x = 306.99 × 129.21
  4. Step 4: Simplify right side
    222.45x = 39,666.18
  5. Step 5: Solve for x
    x = 39,666.18/222.45
  6. Step 6: Final answer
    x = 178.32

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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.