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Finding the Fourth Proportional to 865.05, 1,190.85 and 781.90

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Solution

The fourth proportional to 865.05, 1,190.85 and 781.90 is: 1,076.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.05 : 1,190.85 = 781.90 : x
  2. Step 2: Convert to fraction form
    865.05/1,190.85 = 781.90/x
  3. Step 3: Cross multiply
    865.05x = 1,190.85 × 781.90
  4. Step 4: Simplify right side
    865.05x = 931,125.62
  5. Step 5: Solve for x
    x = 931,125.62/865.05
  6. Step 6: Final answer
    x = 1,076.38

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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.