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Finding the Fourth Proportional to 387.19, 578.36 and 256.11

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Solution

The fourth proportional to 387.19, 578.36 and 256.11 is: 382.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.19 : 578.36 = 256.11 : x
  2. Step 2: Convert to fraction form
    387.19/578.36 = 256.11/x
  3. Step 3: Cross multiply
    387.19x = 578.36 × 256.11
  4. Step 4: Simplify right side
    387.19x = 148,123.78
  5. Step 5: Solve for x
    x = 148,123.78/387.19
  6. Step 6: Final answer
    x = 382.56

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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.