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Finding the Fourth Proportional to 1,208.63, 1,813.13 and 428.89

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Solution

The fourth proportional to 1,208.63, 1,813.13 and 428.89 is: 643.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,208.63 : 1,813.13 = 428.89 : x
  2. Step 2: Convert to fraction form
    1,208.63/1,813.13 = 428.89/x
  3. Step 3: Cross multiply
    1,208.63x = 1,813.13 × 428.89
  4. Step 4: Simplify right side
    1,208.63x = 777,625.70
  5. Step 5: Solve for x
    x = 777,625.70/1,208.63
  6. Step 6: Final answer
    x = 643.39

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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.