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Finding the Fourth Proportional to 908.65, 1,253.95 and 643.56

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Solution

The fourth proportional to 908.65, 1,253.95 and 643.56 is: 888.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    908.65 : 1,253.95 = 643.56 : x
  2. Step 2: Convert to fraction form
    908.65/1,253.95 = 643.56/x
  3. Step 3: Cross multiply
    908.65x = 1,253.95 × 643.56
  4. Step 4: Simplify right side
    908.65x = 806,992.06
  5. Step 5: Solve for x
    x = 806,992.06/908.65
  6. Step 6: Final answer
    x = 888.13

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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.