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Finding the Fourth Proportional to 771.21, 1,064.26 and 421.90

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Solution

The fourth proportional to 771.21, 1,064.26 and 421.90 is: 582.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.21 : 1,064.26 = 421.90 : x
  2. Step 2: Convert to fraction form
    771.21/1,064.26 = 421.90/x
  3. Step 3: Cross multiply
    771.21x = 1,064.26 × 421.90
  4. Step 4: Simplify right side
    771.21x = 449,003.86
  5. Step 5: Solve for x
    x = 449,003.86/771.21
  6. Step 6: Final answer
    x = 582.21

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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.