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Finding the Fourth Proportional to 612.42, 843.96 and 390.99

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Solution

The fourth proportional to 612.42, 843.96 and 390.99 is: 538.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.42 : 843.96 = 390.99 : x
  2. Step 2: Convert to fraction form
    612.42/843.96 = 390.99/x
  3. Step 3: Cross multiply
    612.42x = 843.96 × 390.99
  4. Step 4: Simplify right side
    612.42x = 329,978.70
  5. Step 5: Solve for x
    x = 329,978.70/612.42
  6. Step 6: Final answer
    x = 538.81

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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.