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Finding the Fourth Proportional to 1,079.88, 1,618.86 and 421.30

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Solution

The fourth proportional to 1,079.88, 1,618.86 and 421.30 is: 631.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,079.88 : 1,618.86 = 421.30 : x
  2. Step 2: Convert to fraction form
    1,079.88/1,618.86 = 421.30/x
  3. Step 3: Cross multiply
    1,079.88x = 1,618.86 × 421.30
  4. Step 4: Simplify right side
    1,079.88x = 682,025.72
  5. Step 5: Solve for x
    x = 682,025.72/1,079.88
  6. Step 6: Final answer
    x = 631.58

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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.