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Finding the Fourth Proportional to 1,387.14, 1,916.14 and 1,288.74

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Solution

The fourth proportional to 1,387.14, 1,916.14 and 1,288.74 is: 1,780.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.14 : 1,916.14 = 1,288.74 : x
  2. Step 2: Convert to fraction form
    1,387.14/1,916.14 = 1,288.74/x
  3. Step 3: Cross multiply
    1,387.14x = 1,916.14 × 1,288.74
  4. Step 4: Simplify right side
    1,387.14x = 2,469,406.26
  5. Step 5: Solve for x
    x = 2,469,406.26/1,387.14
  6. Step 6: Final answer
    x = 1,780.21

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.