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Finding the Fourth Proportional to 1,419.66, 2,128.41 and 687.69

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Solution

The fourth proportional to 1,419.66, 2,128.41 and 687.69 is: 1,031.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,419.66 : 2,128.41 = 687.69 : x
  2. Step 2: Convert to fraction form
    1,419.66/2,128.41 = 687.69/x
  3. Step 3: Cross multiply
    1,419.66x = 2,128.41 × 687.69
  4. Step 4: Simplify right side
    1,419.66x = 1,463,686.27
  5. Step 5: Solve for x
    x = 1,463,686.27/1,419.66
  6. Step 6: Final answer
    x = 1,031.01

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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.