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Finding the Fourth Proportional to 409.74, 611.90 and 388.68

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Solution

The fourth proportional to 409.74, 611.90 and 388.68 is: 580.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    409.74 : 611.90 = 388.68 : x
  2. Step 2: Convert to fraction form
    409.74/611.90 = 388.68/x
  3. Step 3: Cross multiply
    409.74x = 611.90 × 388.68
  4. Step 4: Simplify right side
    409.74x = 237,833.29
  5. Step 5: Solve for x
    x = 237,833.29/409.74
  6. Step 6: Final answer
    x = 580.45

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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.