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Finding the Fourth Proportional to 1,991.40, 2,988.72 and 758.99

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Solution

The fourth proportional to 1,991.40, 2,988.72 and 758.99 is: 1,139.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,991.40 : 2,988.72 = 758.99 : x
  2. Step 2: Convert to fraction form
    1,991.40/2,988.72 = 758.99/x
  3. Step 3: Cross multiply
    1,991.40x = 2,988.72 × 758.99
  4. Step 4: Simplify right side
    1,991.40x = 2,268,393.65
  5. Step 5: Solve for x
    x = 2,268,393.65/1,991.40
  6. Step 6: Final answer
    x = 1,139.09

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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.