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Finding the Fourth Proportional to 666.45, 919.70 and 386.75

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Solution

The fourth proportional to 666.45, 919.70 and 386.75 is: 533.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.45 : 919.70 = 386.75 : x
  2. Step 2: Convert to fraction form
    666.45/919.70 = 386.75/x
  3. Step 3: Cross multiply
    666.45x = 919.70 × 386.75
  4. Step 4: Simplify right side
    666.45x = 355,687.44
  5. Step 5: Solve for x
    x = 355,687.44/666.45
  6. Step 6: Final answer
    x = 533.70

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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.