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Finding the Fourth Proportional to 775.89, 1,070.71 and 421.80

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Solution

The fourth proportional to 775.89, 1,070.71 and 421.80 is: 582.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    775.89 : 1,070.71 = 421.80 : x
  2. Step 2: Convert to fraction form
    775.89/1,070.71 = 421.80/x
  3. Step 3: Cross multiply
    775.89x = 1,070.71 × 421.80
  4. Step 4: Simplify right side
    775.89x = 451,626.01
  5. Step 5: Solve for x
    x = 451,626.01/775.89
  6. Step 6: Final answer
    x = 582.07

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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.