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Finding the Fourth Proportional to 1,276.65, 1,761.89 and 717.21

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Solution

The fourth proportional to 1,276.65, 1,761.89 and 717.21 is: 989.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,276.65 : 1,761.89 = 717.21 : x
  2. Step 2: Convert to fraction form
    1,276.65/1,761.89 = 717.21/x
  3. Step 3: Cross multiply
    1,276.65x = 1,761.89 × 717.21
  4. Step 4: Simplify right side
    1,276.65x = 1,263,641.54
  5. Step 5: Solve for x
    x = 1,263,641.54/1,276.65
  6. Step 6: Final answer
    x = 989.81

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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.