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Finding the Fourth Proportional to 857.05, 1,284.79 and 309.11

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Solution

The fourth proportional to 857.05, 1,284.79 and 309.11 is: 463.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.05 : 1,284.79 = 309.11 : x
  2. Step 2: Convert to fraction form
    857.05/1,284.79 = 309.11/x
  3. Step 3: Cross multiply
    857.05x = 1,284.79 × 309.11
  4. Step 4: Simplify right side
    857.05x = 397,141.44
  5. Step 5: Solve for x
    x = 397,141.44/857.05
  6. Step 6: Final answer
    x = 463.38

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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.