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Finding the Fourth Proportional to 1,980.81, 2,971.21 and 811.36

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Solution

The fourth proportional to 1,980.81, 2,971.21 and 811.36 is: 1,217.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,980.81 : 2,971.21 = 811.36 : x
  2. Step 2: Convert to fraction form
    1,980.81/2,971.21 = 811.36/x
  3. Step 3: Cross multiply
    1,980.81x = 2,971.21 × 811.36
  4. Step 4: Simplify right side
    1,980.81x = 2,410,714.53
  5. Step 5: Solve for x
    x = 2,410,714.53/1,980.81
  6. Step 6: Final answer
    x = 1,217.03

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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.