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Finding the Fourth Proportional to 1,185, 1,635.09 and 687.69

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Solution

The fourth proportional to 1,185, 1,635.09 and 687.69 is: 948.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,185 : 1,635.09 = 687.69 : x
  2. Step 2: Convert to fraction form
    1,185/1,635.09 = 687.69/x
  3. Step 3: Cross multiply
    1,185x = 1,635.09 × 687.69
  4. Step 4: Simplify right side
    1,185x = 1,124,435.04
  5. Step 5: Solve for x
    x = 1,124,435.04/1,185
  6. Step 6: Final answer
    x = 948.89

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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.