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Finding the Fourth Proportional to 612.99, 845.64 and 391.91

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Solution

The fourth proportional to 612.99, 845.64 and 391.91 is: 540.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.99 : 845.64 = 391.91 : x
  2. Step 2: Convert to fraction form
    612.99/845.64 = 391.91/x
  3. Step 3: Cross multiply
    612.99x = 845.64 × 391.91
  4. Step 4: Simplify right side
    612.99x = 331,410.54
  5. Step 5: Solve for x
    x = 331,410.54/612.99
  6. Step 6: Final answer
    x = 540.65

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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.