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Finding the Fourth Proportional to 1,661.10, 2,491.71 and 428.51

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Solution

The fourth proportional to 1,661.10, 2,491.71 and 428.51 is: 642.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,661.10 : 2,491.71 = 428.51 : x
  2. Step 2: Convert to fraction form
    1,661.10/2,491.71 = 428.51/x
  3. Step 3: Cross multiply
    1,661.10x = 2,491.71 × 428.51
  4. Step 4: Simplify right side
    1,661.10x = 1,067,720.51
  5. Step 5: Solve for x
    x = 1,067,720.51/1,661.10
  6. Step 6: Final answer
    x = 642.78

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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.