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Finding the Fourth Proportional to 1,318.99, 1,978.49 and 1,238.80

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Solution

The fourth proportional to 1,318.99, 1,978.49 and 1,238.80 is: 1,858.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,318.99 : 1,978.49 = 1,238.80 : x
  2. Step 2: Convert to fraction form
    1,318.99/1,978.49 = 1,238.80/x
  3. Step 3: Cross multiply
    1,318.99x = 1,978.49 × 1,238.80
  4. Step 4: Simplify right side
    1,318.99x = 2,450,953.41
  5. Step 5: Solve for x
    x = 2,450,953.41/1,318.99
  6. Step 6: Final answer
    x = 1,858.20

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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.