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Finding the Fourth Proportional to 1,287.70, 1,929.93 and 998.80

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Solution

The fourth proportional to 1,287.70, 1,929.93 and 998.80 is: 1,496.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.70 : 1,929.93 = 998.80 : x
  2. Step 2: Convert to fraction form
    1,287.70/1,929.93 = 998.80/x
  3. Step 3: Cross multiply
    1,287.70x = 1,929.93 × 998.80
  4. Step 4: Simplify right side
    1,287.70x = 1,927,614.08
  5. Step 5: Solve for x
    x = 1,927,614.08/1,287.70
  6. Step 6: Final answer
    x = 1,496.94

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.