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Finding the Fourth Proportional to 1,291.78, 1,782.60 and 767.86

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Solution

The fourth proportional to 1,291.78, 1,782.60 and 767.86 is: 1,059.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,291.78 : 1,782.60 = 767.86 : x
  2. Step 2: Convert to fraction form
    1,291.78/1,782.60 = 767.86/x
  3. Step 3: Cross multiply
    1,291.78x = 1,782.60 × 767.86
  4. Step 4: Simplify right side
    1,291.78x = 1,368,787.24
  5. Step 5: Solve for x
    x = 1,368,787.24/1,291.78
  6. Step 6: Final answer
    x = 1,059.61

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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.