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Finding the Fourth Proportional to 639.90, 883.08 and 378

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Solution

The fourth proportional to 639.90, 883.08 and 378 is: 521.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.90 : 883.08 = 378 : x
  2. Step 2: Convert to fraction form
    639.90/883.08 = 378/x
  3. Step 3: Cross multiply
    639.90x = 883.08 × 378
  4. Step 4: Simplify right side
    639.90x = 333,804.24
  5. Step 5: Solve for x
    x = 333,804.24/639.90
  6. Step 6: Final answer
    x = 521.65

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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.