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Finding the Fourth Proportional to 427.36, 643.76 and 425.20

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Solution

The fourth proportional to 427.36, 643.76 and 425.20 is: 640.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.36 : 643.76 = 425.20 : x
  2. Step 2: Convert to fraction form
    427.36/643.76 = 425.20/x
  3. Step 3: Cross multiply
    427.36x = 643.76 × 425.20
  4. Step 4: Simplify right side
    427.36x = 273,726.75
  5. Step 5: Solve for x
    x = 273,726.75/427.36
  6. Step 6: Final answer
    x = 640.51

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.