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Finding the Fourth Proportional to 771.97, 1,065.19 and 491.71

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Solution

The fourth proportional to 771.97, 1,065.19 and 491.71 is: 678.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.97 : 1,065.19 = 491.71 : x
  2. Step 2: Convert to fraction form
    771.97/1,065.19 = 491.71/x
  3. Step 3: Cross multiply
    771.97x = 1,065.19 × 491.71
  4. Step 4: Simplify right side
    771.97x = 523,764.57
  5. Step 5: Solve for x
    x = 523,764.57/771.97
  6. Step 6: Final answer
    x = 678.48

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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.