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Finding the Fourth Proportional to 820.19, 1,230.31 and 300.21

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Solution

The fourth proportional to 820.19, 1,230.31 and 300.21 is: 450.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.19 : 1,230.31 = 300.21 : x
  2. Step 2: Convert to fraction form
    820.19/1,230.31 = 300.21/x
  3. Step 3: Cross multiply
    820.19x = 1,230.31 × 300.21
  4. Step 4: Simplify right side
    820.19x = 369,345.44
  5. Step 5: Solve for x
    x = 369,345.44/820.19
  6. Step 6: Final answer
    x = 450.32

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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.