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Finding the Fourth Proportional to 775.09, 1,162.12 and 428.59

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Solution

The fourth proportional to 775.09, 1,162.12 and 428.59 is: 642.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    775.09 : 1,162.12 = 428.59 : x
  2. Step 2: Convert to fraction form
    775.09/1,162.12 = 428.59/x
  3. Step 3: Cross multiply
    775.09x = 1,162.12 × 428.59
  4. Step 4: Simplify right side
    775.09x = 498,070.87
  5. Step 5: Solve for x
    x = 498,070.87/775.09
  6. Step 6: Final answer
    x = 642.60

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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.