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Finding the Fourth Proportional to 220.80, 329.64 and 209.28

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Solution

The fourth proportional to 220.80, 329.64 and 209.28 is: 312.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    220.80 : 329.64 = 209.28 : x
  2. Step 2: Convert to fraction form
    220.80/329.64 = 209.28/x
  3. Step 3: Cross multiply
    220.80x = 329.64 × 209.28
  4. Step 4: Simplify right side
    220.80x = 68,987.06
  5. Step 5: Solve for x
    x = 68,987.06/220.80
  6. Step 6: Final answer
    x = 312.44

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.