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Finding the Fourth Proportional to 813.78, 1,218.84 and 786.45

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Solution

The fourth proportional to 813.78, 1,218.84 and 786.45 is: 1,177.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.78 : 1,218.84 = 786.45 : x
  2. Step 2: Convert to fraction form
    813.78/1,218.84 = 786.45/x
  3. Step 3: Cross multiply
    813.78x = 1,218.84 × 786.45
  4. Step 4: Simplify right side
    813.78x = 958,556.72
  5. Step 5: Solve for x
    x = 958,556.72/813.78
  6. Step 6: Final answer
    x = 1,177.91

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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.