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Finding the Fourth Proportional to 779.11, 1,076.72 and 639.01

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Solution

The fourth proportional to 779.11, 1,076.72 and 639.01 is: 883.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    779.11 : 1,076.72 = 639.01 : x
  2. Step 2: Convert to fraction form
    779.11/1,076.72 = 639.01/x
  3. Step 3: Cross multiply
    779.11x = 1,076.72 × 639.01
  4. Step 4: Simplify right side
    779.11x = 688,034.85
  5. Step 5: Solve for x
    x = 688,034.85/779.11
  6. Step 6: Final answer
    x = 883.10

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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.