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Finding the Fourth Proportional to 1,321.63, 1,981.56 and 628.40

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Solution

The fourth proportional to 1,321.63, 1,981.56 and 628.40 is: 942.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.63 : 1,981.56 = 628.40 : x
  2. Step 2: Convert to fraction form
    1,321.63/1,981.56 = 628.40/x
  3. Step 3: Cross multiply
    1,321.63x = 1,981.56 × 628.40
  4. Step 4: Simplify right side
    1,321.63x = 1,245,212.30
  5. Step 5: Solve for x
    x = 1,245,212.30/1,321.63
  6. Step 6: Final answer
    x = 942.18

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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.