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Finding the Fourth Proportional to 1,079.42, 1,618.88 and 421.31

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Solution

The fourth proportional to 1,079.42, 1,618.88 and 421.31 is: 631.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,079.42 : 1,618.88 = 421.31 : x
  2. Step 2: Convert to fraction form
    1,079.42/1,618.88 = 421.31/x
  3. Step 3: Cross multiply
    1,079.42x = 1,618.88 × 421.31
  4. Step 4: Simplify right side
    1,079.42x = 682,051.91
  5. Step 5: Solve for x
    x = 682,051.91/1,079.42
  6. Step 6: Final answer
    x = 631.87

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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.