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Finding the Fourth Proportional to 613.12, 919.68 and 521.20

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Solution

The fourth proportional to 613.12, 919.68 and 521.20 is: 781.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    613.12 : 919.68 = 521.20 : x
  2. Step 2: Convert to fraction form
    613.12/919.68 = 521.20/x
  3. Step 3: Cross multiply
    613.12x = 919.68 × 521.20
  4. Step 4: Simplify right side
    613.12x = 479,337.22
  5. Step 5: Solve for x
    x = 479,337.22/613.12
  6. Step 6: Final answer
    x = 781.80

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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.