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Finding the Fourth Proportional to 636.87, 878.70 and 388.20

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Solution

The fourth proportional to 636.87, 878.70 and 388.20 is: 535.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    636.87 : 878.70 = 388.20 : x
  2. Step 2: Convert to fraction form
    636.87/878.70 = 388.20/x
  3. Step 3: Cross multiply
    636.87x = 878.70 × 388.20
  4. Step 4: Simplify right side
    636.87x = 341,111.34
  5. Step 5: Solve for x
    x = 341,111.34/636.87
  6. Step 6: Final answer
    x = 535.61

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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.