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Finding the Fourth Proportional to 388.12, 581.90 and 128.04

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Solution

The fourth proportional to 388.12, 581.90 and 128.04 is: 191.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    388.12 : 581.90 = 128.04 : x
  2. Step 2: Convert to fraction form
    388.12/581.90 = 128.04/x
  3. Step 3: Cross multiply
    388.12x = 581.90 × 128.04
  4. Step 4: Simplify right side
    388.12x = 74,502.93
  5. Step 5: Solve for x
    x = 74,502.93/388.12
  6. Step 6: Final answer
    x = 191.96

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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.