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Finding the Fourth Proportional to 613.80, 919.62 and 421.02

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Solution

The fourth proportional to 613.80, 919.62 and 421.02 is: 630.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    613.80 : 919.62 = 421.02 : x
  2. Step 2: Convert to fraction form
    613.80/919.62 = 421.02/x
  3. Step 3: Cross multiply
    613.80x = 919.62 × 421.02
  4. Step 4: Simplify right side
    613.80x = 387,178.41
  5. Step 5: Solve for x
    x = 387,178.41/613.80
  6. Step 6: Final answer
    x = 630.79

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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.