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Finding the Fourth Proportional to 1,388.12, 1,915.80 and 798.65

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Solution

The fourth proportional to 1,388.12, 1,915.80 and 798.65 is: 1,102.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,388.12 : 1,915.80 = 798.65 : x
  2. Step 2: Convert to fraction form
    1,388.12/1,915.80 = 798.65/x
  3. Step 3: Cross multiply
    1,388.12x = 1,915.80 × 798.65
  4. Step 4: Simplify right side
    1,388.12x = 1,530,044.09
  5. Step 5: Solve for x
    x = 1,530,044.09/1,388.12
  6. Step 6: Final answer
    x = 1,102.25

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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.