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Finding the Fourth Proportional to 289.68, 399.90 and 196.40

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Solution

The fourth proportional to 289.68, 399.90 and 196.40 is: 271.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.68 : 399.90 = 196.40 : x
  2. Step 2: Convert to fraction form
    289.68/399.90 = 196.40/x
  3. Step 3: Cross multiply
    289.68x = 399.90 × 196.40
  4. Step 4: Simplify right side
    289.68x = 78,540.36
  5. Step 5: Solve for x
    x = 78,540.36/289.68
  6. Step 6: Final answer
    x = 271.13

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.