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Finding the Fourth Proportional to 612.39, 918.72 and 447.78

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Solution

The fourth proportional to 612.39, 918.72 and 447.78 is: 671.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    612.39 : 918.72 = 447.78 : x
  2. Step 2: Convert to fraction form
    612.39/918.72 = 447.78/x
  3. Step 3: Cross multiply
    612.39x = 918.72 × 447.78
  4. Step 4: Simplify right side
    612.39x = 411,384.44
  5. Step 5: Solve for x
    x = 411,384.44/612.39
  6. Step 6: Final answer
    x = 671.77

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.