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Finding the Fourth Proportional to 1,279.21, 1,765.27 and 781.74

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Solution

The fourth proportional to 1,279.21, 1,765.27 and 781.74 is: 1,078.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279.21 : 1,765.27 = 781.74 : x
  2. Step 2: Convert to fraction form
    1,279.21/1,765.27 = 781.74/x
  3. Step 3: Cross multiply
    1,279.21x = 1,765.27 × 781.74
  4. Step 4: Simplify right side
    1,279.21x = 1,379,982.17
  5. Step 5: Solve for x
    x = 1,379,982.17/1,279.21
  6. Step 6: Final answer
    x = 1,078.78

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1.5x scale

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.