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Finding the Fourth Proportional to 1,687.78, 2,329.08 and 989.14

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Solution

The fourth proportional to 1,687.78, 2,329.08 and 989.14 is: 1,364.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,687.78 : 2,329.08 = 989.14 : x
  2. Step 2: Convert to fraction form
    1,687.78/2,329.08 = 989.14/x
  3. Step 3: Cross multiply
    1,687.78x = 2,329.08 × 989.14
  4. Step 4: Simplify right side
    1,687.78x = 2,303,786.19
  5. Step 5: Solve for x
    x = 2,303,786.19/1,687.78
  6. Step 6: Final answer
    x = 1,364.98

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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.