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Finding the Fourth Proportional to 779.79, 1,169.69 and 642.55

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Solution

The fourth proportional to 779.79, 1,169.69 and 642.55 is: 963.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    779.79 : 1,169.69 = 642.55 : x
  2. Step 2: Convert to fraction form
    779.79/1,169.69 = 642.55/x
  3. Step 3: Cross multiply
    779.79x = 1,169.69 × 642.55
  4. Step 4: Simplify right side
    779.79x = 751,583.98
  5. Step 5: Solve for x
    x = 751,583.98/779.79
  6. Step 6: Final answer
    x = 963.82

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.