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Finding the Fourth Proportional to 1,079.43, 1,618.20 and 639.60

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Solution

The fourth proportional to 1,079.43, 1,618.20 and 639.60 is: 958.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,079.43 : 1,618.20 = 639.60 : x
  2. Step 2: Convert to fraction form
    1,079.43/1,618.20 = 639.60/x
  3. Step 3: Cross multiply
    1,079.43x = 1,618.20 × 639.60
  4. Step 4: Simplify right side
    1,079.43x = 1,035,000.72
  5. Step 5: Solve for x
    x = 1,035,000.72/1,079.43
  6. Step 6: Final answer
    x = 958.84

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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.