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Finding the Fourth Proportional to 643.36, 965 and 210.40

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Solution

The fourth proportional to 643.36, 965 and 210.40 is: 315.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.36 : 965 = 210.40 : x
  2. Step 2: Convert to fraction form
    643.36/965 = 210.40/x
  3. Step 3: Cross multiply
    643.36x = 965 × 210.40
  4. Step 4: Simplify right side
    643.36x = 203,036
  5. Step 5: Solve for x
    x = 203,036/643.36
  6. Step 6: Final answer
    x = 315.59

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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.