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Finding the Fourth Proportional to 1,079.64, 1,489.86 and 631.80

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Solution

The fourth proportional to 1,079.64, 1,489.86 and 631.80 is: 871.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,079.64 : 1,489.86 = 631.80 : x
  2. Step 2: Convert to fraction form
    1,079.64/1,489.86 = 631.80/x
  3. Step 3: Cross multiply
    1,079.64x = 1,489.86 × 631.80
  4. Step 4: Simplify right side
    1,079.64x = 941,293.55
  5. Step 5: Solve for x
    x = 941,293.55/1,079.64
  6. Step 6: Final answer
    x = 871.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.