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Finding the Fourth Proportional to 1,279.78, 1,764.32 and 859.40

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Solution

The fourth proportional to 1,279.78, 1,764.32 and 859.40 is: 1,184.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279.78 : 1,764.32 = 859.40 : x
  2. Step 2: Convert to fraction form
    1,279.78/1,764.32 = 859.40/x
  3. Step 3: Cross multiply
    1,279.78x = 1,764.32 × 859.40
  4. Step 4: Simplify right side
    1,279.78x = 1,516,256.61
  5. Step 5: Solve for x
    x = 1,516,256.61/1,279.78
  6. Step 6: Final answer
    x = 1,184.78

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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.