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Finding the Fourth Proportional to 1,921.01, 2,880.90 and 687.71

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Solution

The fourth proportional to 1,921.01, 2,880.90 and 687.71 is: 1,031.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,921.01 : 2,880.90 = 687.71 : x
  2. Step 2: Convert to fraction form
    1,921.01/2,880.90 = 687.71/x
  3. Step 3: Cross multiply
    1,921.01x = 2,880.90 × 687.71
  4. Step 4: Simplify right side
    1,921.01x = 1,981,230.94
  5. Step 5: Solve for x
    x = 1,981,230.94/1,921.01
  6. Step 6: Final answer
    x = 1,031.35

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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.