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Finding the Fourth Proportional to 645.20, 970 and 642

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Solution

The fourth proportional to 645.20, 970 and 642 is: 965.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.20 : 970 = 642 : x
  2. Step 2: Convert to fraction form
    645.20/970 = 642/x
  3. Step 3: Cross multiply
    645.20x = 970 × 642
  4. Step 4: Simplify right side
    645.20x = 622,740
  5. Step 5: Solve for x
    x = 622,740/645.20
  6. Step 6: Final answer
    x = 965.19

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These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.