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Finding the Fourth Proportional to 874.80, 1,311.30 and 509.40

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Solution

The fourth proportional to 874.80, 1,311.30 and 509.40 is: 763.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    874.80 : 1,311.30 = 509.40 : x
  2. Step 2: Convert to fraction form
    874.80/1,311.30 = 509.40/x
  3. Step 3: Cross multiply
    874.80x = 1,311.30 × 509.40
  4. Step 4: Simplify right side
    874.80x = 667,976.22
  5. Step 5: Solve for x
    x = 667,976.22/874.80
  6. Step 6: Final answer
    x = 763.58

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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.