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Finding the Fourth Proportional to 711.13, 981.31 and 396.40

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Solution

The fourth proportional to 711.13, 981.31 and 396.40 is: 547.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    711.13 : 981.31 = 396.40 : x
  2. Step 2: Convert to fraction form
    711.13/981.31 = 396.40/x
  3. Step 3: Cross multiply
    711.13x = 981.31 × 396.40
  4. Step 4: Simplify right side
    711.13x = 388,991.28
  5. Step 5: Solve for x
    x = 388,991.28/711.13
  6. Step 6: Final answer
    x = 547.00

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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.