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Finding the Fourth Proportional to 781.56, 1,170.72 and 396

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Solution

The fourth proportional to 781.56, 1,170.72 and 396 is: 593.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.56 : 1,170.72 = 396 : x
  2. Step 2: Convert to fraction form
    781.56/1,170.72 = 396/x
  3. Step 3: Cross multiply
    781.56x = 1,170.72 × 396
  4. Step 4: Simplify right side
    781.56x = 463,605.12
  5. Step 5: Solve for x
    x = 463,605.12/781.56
  6. Step 6: Final answer
    x = 593.18

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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.