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Finding the Fourth Proportional to 1,322.56, 1,987.72 and 639.04

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Solution

The fourth proportional to 1,322.56, 1,987.72 and 639.04 is: 960.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,322.56 : 1,987.72 = 639.04 : x
  2. Step 2: Convert to fraction form
    1,322.56/1,987.72 = 639.04/x
  3. Step 3: Cross multiply
    1,322.56x = 1,987.72 × 639.04
  4. Step 4: Simplify right side
    1,322.56x = 1,270,232.59
  5. Step 5: Solve for x
    x = 1,270,232.59/1,322.56
  6. Step 6: Final answer
    x = 960.43

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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.