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Finding the Fourth Proportional to 779.52, 1,074.12 and 639.16

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Solution

The fourth proportional to 779.52, 1,074.12 and 639.16 is: 880.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    779.52 : 1,074.12 = 639.16 : x
  2. Step 2: Convert to fraction form
    779.52/1,074.12 = 639.16/x
  3. Step 3: Cross multiply
    779.52x = 1,074.12 × 639.16
  4. Step 4: Simplify right side
    779.52x = 686,534.54
  5. Step 5: Solve for x
    x = 686,534.54/779.52
  6. Step 6: Final answer
    x = 880.71

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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.