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Finding the Fourth Proportional to 871.30, 1,300.20 and 779

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Solution

The fourth proportional to 871.30, 1,300.20 and 779 is: 1,162.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.30 : 1,300.20 = 779 : x
  2. Step 2: Convert to fraction form
    871.30/1,300.20 = 779/x
  3. Step 3: Cross multiply
    871.30x = 1,300.20 × 779
  4. Step 4: Simplify right side
    871.30x = 1,012,855.80
  5. Step 5: Solve for x
    x = 1,012,855.80/871.30
  6. Step 6: Final answer
    x = 1,162.47

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.