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Finding the Fourth Proportional to 771, 1,064 and 421.72

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Solution

The fourth proportional to 771, 1,064 and 421.72 is: 581.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    771 : 1,064 = 421.72 : x
  2. Step 2: Convert to fraction form
    771/1,064 = 421.72/x
  3. Step 3: Cross multiply
    771x = 1,064 × 421.72
  4. Step 4: Simplify right side
    771x = 448,710.08
  5. Step 5: Solve for x
    x = 448,710.08/771
  6. Step 6: Final answer
    x = 581.98

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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.