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Finding the Fourth Proportional to 781.06, 1,170.20 and 664.42

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Solution

The fourth proportional to 781.06, 1,170.20 and 664.42 is: 995.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.06 : 1,170.20 = 664.42 : x
  2. Step 2: Convert to fraction form
    781.06/1,170.20 = 664.42/x
  3. Step 3: Cross multiply
    781.06x = 1,170.20 × 664.42
  4. Step 4: Simplify right side
    781.06x = 777,504.28
  5. Step 5: Solve for x
    x = 777,504.28/781.06
  6. Step 6: Final answer
    x = 995.45

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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.