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Finding the Fourth Proportional to 1,081.65, 1,491.70 and 687.99

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Solution

The fourth proportional to 1,081.65, 1,491.70 and 687.99 is: 948.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,081.65 : 1,491.70 = 687.99 : x
  2. Step 2: Convert to fraction form
    1,081.65/1,491.70 = 687.99/x
  3. Step 3: Cross multiply
    1,081.65x = 1,491.70 × 687.99
  4. Step 4: Simplify right side
    1,081.65x = 1,026,274.68
  5. Step 5: Solve for x
    x = 1,026,274.68/1,081.65
  6. Step 6: Final answer
    x = 948.80

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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.