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Finding the Fourth Proportional to 1,987.26, 2,980.81 and 688.83

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Solution

The fourth proportional to 1,987.26, 2,980.81 and 688.83 is: 1,033.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,987.26 : 2,980.81 = 688.83 : x
  2. Step 2: Convert to fraction form
    1,987.26/2,980.81 = 688.83/x
  3. Step 3: Cross multiply
    1,987.26x = 2,980.81 × 688.83
  4. Step 4: Simplify right side
    1,987.26x = 2,053,271.35
  5. Step 5: Solve for x
    x = 2,053,271.35/1,987.26
  6. Step 6: Final answer
    x = 1,033.22

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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.