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Finding the Fourth Proportional to 813, 1,219.86 and 319.32

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Solution

The fourth proportional to 813, 1,219.86 and 319.32 is: 479.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    813 : 1,219.86 = 319.32 : x
  2. Step 2: Convert to fraction form
    813/1,219.86 = 319.32/x
  3. Step 3: Cross multiply
    813x = 1,219.86 × 319.32
  4. Step 4: Simplify right side
    813x = 389,525.70
  5. Step 5: Solve for x
    x = 389,525.70/813
  6. Step 6: Final answer
    x = 479.12

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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.