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Finding the Fourth Proportional to 858.20, 1,287.52 and 447.21

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Solution

The fourth proportional to 858.20, 1,287.52 and 447.21 is: 670.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.20 : 1,287.52 = 447.21 : x
  2. Step 2: Convert to fraction form
    858.20/1,287.52 = 447.21/x
  3. Step 3: Cross multiply
    858.20x = 1,287.52 × 447.21
  4. Step 4: Simplify right side
    858.20x = 575,790.70
  5. Step 5: Solve for x
    x = 575,790.70/858.20
  6. Step 6: Final answer
    x = 670.93

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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.