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Finding the Fourth Proportional to 666.50, 919.46 and 400.78

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Solution

The fourth proportional to 666.50, 919.46 and 400.78 is: 552.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.50 : 919.46 = 400.78 : x
  2. Step 2: Convert to fraction form
    666.50/919.46 = 400.78/x
  3. Step 3: Cross multiply
    666.50x = 919.46 × 400.78
  4. Step 4: Simplify right side
    666.50x = 368,501.18
  5. Step 5: Solve for x
    x = 368,501.18/666.50
  6. Step 6: Final answer
    x = 552.89

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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.