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Finding the Fourth Proportional to 643.98, 965.76 and 210.90

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Solution

The fourth proportional to 643.98, 965.76 and 210.90 is: 316.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.98 : 965.76 = 210.90 : x
  2. Step 2: Convert to fraction form
    643.98/965.76 = 210.90/x
  3. Step 3: Cross multiply
    643.98x = 965.76 × 210.90
  4. Step 4: Simplify right side
    643.98x = 203,678.78
  5. Step 5: Solve for x
    x = 203,678.78/643.98
  6. Step 6: Final answer
    x = 316.28

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.