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Finding the Fourth Proportional to 1,238.88, 1,711.10 and 987.65

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Solution

The fourth proportional to 1,238.88, 1,711.10 and 987.65 is: 1,364.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,238.88 : 1,711.10 = 987.65 : x
  2. Step 2: Convert to fraction form
    1,238.88/1,711.10 = 987.65/x
  3. Step 3: Cross multiply
    1,238.88x = 1,711.10 × 987.65
  4. Step 4: Simplify right side
    1,238.88x = 1,689,954.42
  5. Step 5: Solve for x
    x = 1,689,954.42/1,238.88
  6. Step 6: Final answer
    x = 1,364.10

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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.