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Finding the Fourth Proportional to 858.51, 1,287.12 and 447.21

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Solution

The fourth proportional to 858.51, 1,287.12 and 447.21 is: 670.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.51 : 1,287.12 = 447.21 : x
  2. Step 2: Convert to fraction form
    858.51/1,287.12 = 447.21/x
  3. Step 3: Cross multiply
    858.51x = 1,287.12 × 447.21
  4. Step 4: Simplify right side
    858.51x = 575,612.94
  5. Step 5: Solve for x
    x = 575,612.94/858.51
  6. Step 6: Final answer
    x = 670.48

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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.