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Finding the Fourth Proportional to 639.78, 880.79 and 556.84

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Solution

The fourth proportional to 639.78, 880.79 and 556.84 is: 766.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.78 : 880.79 = 556.84 : x
  2. Step 2: Convert to fraction form
    639.78/880.79 = 556.84/x
  3. Step 3: Cross multiply
    639.78x = 880.79 × 556.84
  4. Step 4: Simplify right side
    639.78x = 490,459.10
  5. Step 5: Solve for x
    x = 490,459.10/639.78
  6. Step 6: Final answer
    x = 766.61

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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.