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Finding the Fourth Proportional to 1,805.40, 2,491.38 and 1,215

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Solution

The fourth proportional to 1,805.40, 2,491.38 and 1,215 is: 1,676.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,805.40 : 2,491.38 = 1,215 : x
  2. Step 2: Convert to fraction form
    1,805.40/2,491.38 = 1,215/x
  3. Step 3: Cross multiply
    1,805.40x = 2,491.38 × 1,215
  4. Step 4: Simplify right side
    1,805.40x = 3,027,026.70
  5. Step 5: Solve for x
    x = 3,027,026.70/1,805.40
  6. Step 6: Final answer
    x = 1,676.65

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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.