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Finding the Fourth Proportional to 643.68, 965.59 and 210.91

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Solution

The fourth proportional to 643.68, 965.59 and 210.91 is: 316.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.68 : 965.59 = 210.91 : x
  2. Step 2: Convert to fraction form
    643.68/965.59 = 210.91/x
  3. Step 3: Cross multiply
    643.68x = 965.59 × 210.91
  4. Step 4: Simplify right side
    643.68x = 203,652.59
  5. Step 5: Solve for x
    x = 203,652.59/643.68
  6. Step 6: Final answer
    x = 316.39

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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.