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Finding the Fourth Proportional to 666.90, 920.39 and 387.11

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Solution

The fourth proportional to 666.90, 920.39 and 387.11 is: 534.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.90 : 920.39 = 387.11 : x
  2. Step 2: Convert to fraction form
    666.90/920.39 = 387.11/x
  3. Step 3: Cross multiply
    666.90x = 920.39 × 387.11
  4. Step 4: Simplify right side
    666.90x = 356,292.54
  5. Step 5: Solve for x
    x = 356,292.54/666.90
  6. Step 6: Final answer
    x = 534.25

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1.5x scale

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.