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Finding the Fourth Proportional to 1,871.20, 2,806.55 and 638.58

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Solution

The fourth proportional to 1,871.20, 2,806.55 and 638.58 is: 957.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,871.20 : 2,806.55 = 638.58 : x
  2. Step 2: Convert to fraction form
    1,871.20/2,806.55 = 638.58/x
  3. Step 3: Cross multiply
    1,871.20x = 2,806.55 × 638.58
  4. Step 4: Simplify right side
    1,871.20x = 1,792,203.51
  5. Step 5: Solve for x
    x = 1,792,203.51/1,871.20
  6. Step 6: Final answer
    x = 957.79

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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.