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Finding the Fourth Proportional to 1,321.66, 1,981.53 and 859.90

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Solution

The fourth proportional to 1,321.66, 1,981.53 and 859.90 is: 1,289.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.66 : 1,981.53 = 859.90 : x
  2. Step 2: Convert to fraction form
    1,321.66/1,981.53 = 859.90/x
  3. Step 3: Cross multiply
    1,321.66x = 1,981.53 × 859.90
  4. Step 4: Simplify right side
    1,321.66x = 1,703,917.65
  5. Step 5: Solve for x
    x = 1,703,917.65/1,321.66
  6. Step 6: Final answer
    x = 1,289.23

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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.