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Finding the Fourth Proportional to 813.21, 1,219.99 and 380.13

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Solution

The fourth proportional to 813.21, 1,219.99 and 380.13 is: 570.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.21 : 1,219.99 = 380.13 : x
  2. Step 2: Convert to fraction form
    813.21/1,219.99 = 380.13/x
  3. Step 3: Cross multiply
    813.21x = 1,219.99 × 380.13
  4. Step 4: Simplify right side
    813.21x = 463,754.80
  5. Step 5: Solve for x
    x = 463,754.80/813.21
  6. Step 6: Final answer
    x = 570.28

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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.