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Finding the Fourth Proportional to 771.12, 1,064.16 and 421.80

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Solution

The fourth proportional to 771.12, 1,064.16 and 421.80 is: 582.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    771.12 : 1,064.16 = 421.80 : x
  2. Step 2: Convert to fraction form
    771.12/1,064.16 = 421.80/x
  3. Step 3: Cross multiply
    771.12x = 1,064.16 × 421.80
  4. Step 4: Simplify right side
    771.12x = 448,855.26
  5. Step 5: Solve for x
    x = 448,855.26/771.12
  6. Step 6: Final answer
    x = 582.09

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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.