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Finding the Fourth Proportional to 809.15, 1,208.24 and 642.75

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Solution

The fourth proportional to 809.15, 1,208.24 and 642.75 is: 959.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.15 : 1,208.24 = 642.75 : x
  2. Step 2: Convert to fraction form
    809.15/1,208.24 = 642.75/x
  3. Step 3: Cross multiply
    809.15x = 1,208.24 × 642.75
  4. Step 4: Simplify right side
    809.15x = 776,599.63
  5. Step 5: Solve for x
    x = 776,599.63/809.15
  6. Step 6: Final answer
    x = 959.77

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.