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Finding the Fourth Proportional to 393.18, 543.15 and 315.42

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Solution

The fourth proportional to 393.18, 543.15 and 315.42 is: 435.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.18 : 543.15 = 315.42 : x
  2. Step 2: Convert to fraction form
    393.18/543.15 = 315.42/x
  3. Step 3: Cross multiply
    393.18x = 543.15 × 315.42
  4. Step 4: Simplify right side
    393.18x = 171,320.37
  5. Step 5: Solve for x
    x = 171,320.37/393.18
  6. Step 6: Final answer
    x = 435.73

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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.