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Finding the Fourth Proportional to 813.26, 1,219.90 and 319.70

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Solution

The fourth proportional to 813.26, 1,219.90 and 319.70 is: 479.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.26 : 1,219.90 = 319.70 : x
  2. Step 2: Convert to fraction form
    813.26/1,219.90 = 319.70/x
  3. Step 3: Cross multiply
    813.26x = 1,219.90 × 319.70
  4. Step 4: Simplify right side
    813.26x = 390,002.03
  5. Step 5: Solve for x
    x = 390,002.03/813.26
  6. Step 6: Final answer
    x = 479.55

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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.