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Finding the Fourth Proportional to 393.15, 543.18 and 389.31

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Solution

The fourth proportional to 393.15, 543.18 and 389.31 is: 537.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.15 : 543.18 = 389.31 : x
  2. Step 2: Convert to fraction form
    393.15/543.18 = 389.31/x
  3. Step 3: Cross multiply
    393.15x = 543.18 × 389.31
  4. Step 4: Simplify right side
    393.15x = 211,465.41
  5. Step 5: Solve for x
    x = 211,465.41/393.15
  6. Step 6: Final answer
    x = 537.87

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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.