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Finding the Fourth Proportional to 666.82, 919.92 and 491.86

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Solution

The fourth proportional to 666.82, 919.92 and 491.86 is: 678.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.82 : 919.92 = 491.86 : x
  2. Step 2: Convert to fraction form
    666.82/919.92 = 491.86/x
  3. Step 3: Cross multiply
    666.82x = 919.92 × 491.86
  4. Step 4: Simplify right side
    666.82x = 452,471.85
  5. Step 5: Solve for x
    x = 452,471.85/666.82
  6. Step 6: Final answer
    x = 678.55

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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.