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Finding the Fourth Proportional to 613.90, 921.15 and 289.21

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Solution

The fourth proportional to 613.90, 921.15 and 289.21 is: 433.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    613.90 : 921.15 = 289.21 : x
  2. Step 2: Convert to fraction form
    613.90/921.15 = 289.21/x
  3. Step 3: Cross multiply
    613.90x = 921.15 × 289.21
  4. Step 4: Simplify right side
    613.90x = 266,405.79
  5. Step 5: Solve for x
    x = 266,405.79/613.90
  6. Step 6: Final answer
    x = 433.96

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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.