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Finding the Fourth Proportional to 645.64, 968.43 and 212.80

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Solution

The fourth proportional to 645.64, 968.43 and 212.80 is: 319.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.64 : 968.43 = 212.80 : x
  2. Step 2: Convert to fraction form
    645.64/968.43 = 212.80/x
  3. Step 3: Cross multiply
    645.64x = 968.43 × 212.80
  4. Step 4: Simplify right side
    645.64x = 206,081.90
  5. Step 5: Solve for x
    x = 206,081.90/645.64
  6. Step 6: Final answer
    x = 319.19

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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.