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Finding the Fourth Proportional to 858.58, 1,287.86 and 447.90

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Solution

The fourth proportional to 858.58, 1,287.86 and 447.90 is: 671.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.58 : 1,287.86 = 447.90 : x
  2. Step 2: Convert to fraction form
    858.58/1,287.86 = 447.90/x
  3. Step 3: Cross multiply
    858.58x = 1,287.86 × 447.90
  4. Step 4: Simplify right side
    858.58x = 576,832.49
  5. Step 5: Solve for x
    x = 576,832.49/858.58
  6. Step 6: Final answer
    x = 671.84

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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.