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Finding the Fourth Proportional to 219.65, 328.77 and 128.07

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Solution

The fourth proportional to 219.65, 328.77 and 128.07 is: 191.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    219.65 : 328.77 = 128.07 : x
  2. Step 2: Convert to fraction form
    219.65/328.77 = 128.07/x
  3. Step 3: Cross multiply
    219.65x = 328.77 × 128.07
  4. Step 4: Simplify right side
    219.65x = 42,105.57
  5. Step 5: Solve for x
    x = 42,105.57/219.65
  6. Step 6: Final answer
    x = 191.70

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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.