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Finding the Fourth Proportional to 666.66, 919.89 and 386.91

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Solution

The fourth proportional to 666.66, 919.89 and 386.91 is: 533.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.66 : 919.89 = 386.91 : x
  2. Step 2: Convert to fraction form
    666.66/919.89 = 386.91/x
  3. Step 3: Cross multiply
    666.66x = 919.89 × 386.91
  4. Step 4: Simplify right side
    666.66x = 355,914.64
  5. Step 5: Solve for x
    x = 355,914.64/666.66
  6. Step 6: Final answer
    x = 533.87

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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.