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Finding the Fourth Proportional to 1,321.90, 1,981.68 and 499.60

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Solution

The fourth proportional to 1,321.90, 1,981.68 and 499.60 is: 748.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.90 : 1,981.68 = 499.60 : x
  2. Step 2: Convert to fraction form
    1,321.90/1,981.68 = 499.60/x
  3. Step 3: Cross multiply
    1,321.90x = 1,981.68 × 499.60
  4. Step 4: Simplify right side
    1,321.90x = 990,049.81
  5. Step 5: Solve for x
    x = 990,049.81/1,321.90
  6. Step 6: Final answer
    x = 748.96

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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.