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Finding the Fourth Proportional to 219.30, 328.85 and 128.03

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Solution

The fourth proportional to 219.30, 328.85 and 128.03 is: 191.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    219.30 : 328.85 = 128.03 : x
  2. Step 2: Convert to fraction form
    219.30/328.85 = 128.03/x
  3. Step 3: Cross multiply
    219.30x = 328.85 × 128.03
  4. Step 4: Simplify right side
    219.30x = 42,100.38
  5. Step 5: Solve for x
    x = 42,100.38/219.30
  6. Step 6: Final answer
    x = 191.98

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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.