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Finding the Fourth Proportional to 666.90, 919.89 and 401.22

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Solution

The fourth proportional to 666.90, 919.89 and 401.22 is: 553.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.90 : 919.89 = 401.22 : x
  2. Step 2: Convert to fraction form
    666.90/919.89 = 401.22/x
  3. Step 3: Cross multiply
    666.90x = 919.89 × 401.22
  4. Step 4: Simplify right side
    666.90x = 369,078.27
  5. Step 5: Solve for x
    x = 369,078.27/666.90
  6. Step 6: Final answer
    x = 553.42

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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.