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Finding the Fourth Proportional to 666.47, 919.85 and 386.88

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Solution

The fourth proportional to 666.47, 919.85 and 386.88 is: 533.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.47 : 919.85 = 386.88 : x
  2. Step 2: Convert to fraction form
    666.47/919.85 = 386.88/x
  3. Step 3: Cross multiply
    666.47x = 919.85 × 386.88
  4. Step 4: Simplify right side
    666.47x = 355,869.63
  5. Step 5: Solve for x
    x = 355,869.63/666.47
  6. Step 6: Final answer
    x = 533.97

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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.