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Finding the Fourth Proportional to 851.25, 1,175.21 and 643.89

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Solution

The fourth proportional to 851.25, 1,175.21 and 643.89 is: 888.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    851.25 : 1,175.21 = 643.89 : x
  2. Step 2: Convert to fraction form
    851.25/1,175.21 = 643.89/x
  3. Step 3: Cross multiply
    851.25x = 1,175.21 × 643.89
  4. Step 4: Simplify right side
    851.25x = 756,702.75
  5. Step 5: Solve for x
    x = 756,702.75/851.25
  6. Step 6: Final answer
    x = 888.93

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.