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Finding the Fourth Proportional to 666.39, 919.47 and 386.66

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Solution

The fourth proportional to 666.39, 919.47 and 386.66 is: 533.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.39 : 919.47 = 386.66 : x
  2. Step 2: Convert to fraction form
    666.39/919.47 = 386.66/x
  3. Step 3: Cross multiply
    666.39x = 919.47 × 386.66
  4. Step 4: Simplify right side
    666.39x = 355,517.67
  5. Step 5: Solve for x
    x = 355,517.67/666.39
  6. Step 6: Final answer
    x = 533.50

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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.