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Finding the Fourth Proportional to 778.91, 1,161.89 and 720.78

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Solution

The fourth proportional to 778.91, 1,161.89 and 720.78 is: 1,075.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.91 : 1,161.89 = 720.78 : x
  2. Step 2: Convert to fraction form
    778.91/1,161.89 = 720.78/x
  3. Step 3: Cross multiply
    778.91x = 1,161.89 × 720.78
  4. Step 4: Simplify right side
    778.91x = 837,463.47
  5. Step 5: Solve for x
    x = 837,463.47/778.91
  6. Step 6: Final answer
    x = 1,075.18

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.