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Finding the Fourth Proportional to 1,321.81, 1,980.07 and 629.15

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Solution

The fourth proportional to 1,321.81, 1,980.07 and 629.15 is: 942.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.81 : 1,980.07 = 629.15 : x
  2. Step 2: Convert to fraction form
    1,321.81/1,980.07 = 629.15/x
  3. Step 3: Cross multiply
    1,321.81x = 1,980.07 × 629.15
  4. Step 4: Simplify right side
    1,321.81x = 1,245,761.04
  5. Step 5: Solve for x
    x = 1,245,761.04/1,321.81
  6. Step 6: Final answer
    x = 942.47

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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.