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Finding the Fourth Proportional to 1,210.78, 1,814.94 and 820.82

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Solution

The fourth proportional to 1,210.78, 1,814.94 and 820.82 is: 1,230.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,210.78 : 1,814.94 = 820.82 : x
  2. Step 2: Convert to fraction form
    1,210.78/1,814.94 = 820.82/x
  3. Step 3: Cross multiply
    1,210.78x = 1,814.94 × 820.82
  4. Step 4: Simplify right side
    1,210.78x = 1,489,739.05
  5. Step 5: Solve for x
    x = 1,489,739.05/1,210.78
  6. Step 6: Final answer
    x = 1,230.40

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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.