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Finding the Fourth Proportional to 1,321.03, 1,978.80 and 628.30

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Solution

The fourth proportional to 1,321.03, 1,978.80 and 628.30 is: 941.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.03 : 1,978.80 = 628.30 : x
  2. Step 2: Convert to fraction form
    1,321.03/1,978.80 = 628.30/x
  3. Step 3: Cross multiply
    1,321.03x = 1,978.80 × 628.30
  4. Step 4: Simplify right side
    1,321.03x = 1,243,280.04
  5. Step 5: Solve for x
    x = 1,243,280.04/1,321.03
  6. Step 6: Final answer
    x = 941.14

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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.