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Finding the Fourth Proportional to 388.12, 535.78 and 256.90

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Solution

The fourth proportional to 388.12, 535.78 and 256.90 is: 354.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    388.12 : 535.78 = 256.90 : x
  2. Step 2: Convert to fraction form
    388.12/535.78 = 256.90/x
  3. Step 3: Cross multiply
    388.12x = 535.78 × 256.90
  4. Step 4: Simplify right side
    388.12x = 137,641.88
  5. Step 5: Solve for x
    x = 137,641.88/388.12
  6. Step 6: Final answer
    x = 354.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.