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Finding the Fourth Proportional to 1,871.28, 2,806 and 638.28

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Solution

The fourth proportional to 1,871.28, 2,806 and 638.28 is: 957.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,871.28 : 2,806 = 638.28 : x
  2. Step 2: Convert to fraction form
    1,871.28/2,806 = 638.28/x
  3. Step 3: Cross multiply
    1,871.28x = 2,806 × 638.28
  4. Step 4: Simplify right side
    1,871.28x = 1,791,013.68
  5. Step 5: Solve for x
    x = 1,791,013.68/1,871.28
  6. Step 6: Final answer
    x = 957.11

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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.