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Finding the Fourth Proportional to 639.42, 883.35 and 630.78

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Solution

The fourth proportional to 639.42, 883.35 and 630.78 is: 871.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.42 : 883.35 = 630.78 : x
  2. Step 2: Convert to fraction form
    639.42/883.35 = 630.78/x
  3. Step 3: Cross multiply
    639.42x = 883.35 × 630.78
  4. Step 4: Simplify right side
    639.42x = 557,199.51
  5. Step 5: Solve for x
    x = 557,199.51/639.42
  6. Step 6: Final answer
    x = 871.41

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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.