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Finding the Fourth Proportional to 643.67, 888.21 and 378.12

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Solution

The fourth proportional to 643.67, 888.21 and 378.12 is: 521.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.67 : 888.21 = 378.12 : x
  2. Step 2: Convert to fraction form
    643.67/888.21 = 378.12/x
  3. Step 3: Cross multiply
    643.67x = 888.21 × 378.12
  4. Step 4: Simplify right side
    643.67x = 335,849.97
  5. Step 5: Solve for x
    x = 335,849.97/643.67
  6. Step 6: Final answer
    x = 521.78

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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.