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Finding the Fourth Proportional to 640.78, 884.21 and 378.76

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Solution

The fourth proportional to 640.78, 884.21 and 378.76 is: 522.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.78 : 884.21 = 378.76 : x
  2. Step 2: Convert to fraction form
    640.78/884.21 = 378.76/x
  3. Step 3: Cross multiply
    640.78x = 884.21 × 378.76
  4. Step 4: Simplify right side
    640.78x = 334,903.38
  5. Step 5: Solve for x
    x = 334,903.38/640.78
  6. Step 6: Final answer
    x = 522.65

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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.