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Finding the Fourth Proportional to 1,391.90, 2,083.80 and 1,311.80

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Solution

The fourth proportional to 1,391.90, 2,083.80 and 1,311.80 is: 1,963.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.90 : 2,083.80 = 1,311.80 : x
  2. Step 2: Convert to fraction form
    1,391.90/2,083.80 = 1,311.80/x
  3. Step 3: Cross multiply
    1,391.90x = 2,083.80 × 1,311.80
  4. Step 4: Simplify right side
    1,391.90x = 2,733,528.84
  5. Step 5: Solve for x
    x = 2,733,528.84/1,391.90
  6. Step 6: Final answer
    x = 1,963.88

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1.5x scale

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.