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Finding the Fourth Proportional to 1,311.78, 1,968.38 and 490.20

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Solution

The fourth proportional to 1,311.78, 1,968.38 and 490.20 is: 735.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,311.78 : 1,968.38 = 490.20 : x
  2. Step 2: Convert to fraction form
    1,311.78/1,968.38 = 490.20/x
  3. Step 3: Cross multiply
    1,311.78x = 1,968.38 × 490.20
  4. Step 4: Simplify right side
    1,311.78x = 964,899.88
  5. Step 5: Solve for x
    x = 964,899.88/1,311.78
  6. Step 6: Final answer
    x = 735.57

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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.