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Finding the Fourth Proportional to 666.21, 919.49 and 400.86

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Solution

The fourth proportional to 666.21, 919.49 and 400.86 is: 553.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.21 : 919.49 = 400.86 : x
  2. Step 2: Convert to fraction form
    666.21/919.49 = 400.86/x
  3. Step 3: Cross multiply
    666.21x = 919.49 × 400.86
  4. Step 4: Simplify right side
    666.21x = 368,591.21
  5. Step 5: Solve for x
    x = 368,591.21/666.21
  6. Step 6: Final answer
    x = 553.27

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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.