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Finding the Fourth Proportional to 643.51, 888.28 and 391.46

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Solution

The fourth proportional to 643.51, 888.28 and 391.46 is: 540.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.51 : 888.28 = 391.46 : x
  2. Step 2: Convert to fraction form
    643.51/888.28 = 391.46/x
  3. Step 3: Cross multiply
    643.51x = 888.28 × 391.46
  4. Step 4: Simplify right side
    643.51x = 347,723.72
  5. Step 5: Solve for x
    x = 347,723.72/643.51
  6. Step 6: Final answer
    x = 540.35

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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.