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Finding the Fourth Proportional to 1,288.50, 1,778.13 and 822.78

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Solution

The fourth proportional to 1,288.50, 1,778.13 and 822.78 is: 1,135.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.50 : 1,778.13 = 822.78 : x
  2. Step 2: Convert to fraction form
    1,288.50/1,778.13 = 822.78/x
  3. Step 3: Cross multiply
    1,288.50x = 1,778.13 × 822.78
  4. Step 4: Simplify right side
    1,288.50x = 1,463,009.80
  5. Step 5: Solve for x
    x = 1,463,009.80/1,288.50
  6. Step 6: Final answer
    x = 1,135.44

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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.