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Finding the Fourth Proportional to 858.88, 1,287.12 and 666.56

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Solution

The fourth proportional to 858.88, 1,287.12 and 666.56 is: 998.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.88 : 1,287.12 = 666.56 : x
  2. Step 2: Convert to fraction form
    858.88/1,287.12 = 666.56/x
  3. Step 3: Cross multiply
    858.88x = 1,287.12 × 666.56
  4. Step 4: Simplify right side
    858.88x = 857,942.71
  5. Step 5: Solve for x
    x = 857,942.71/858.88
  6. Step 6: Final answer
    x = 998.91

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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.