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Finding the Fourth Proportional to 1,212.28, 1,818.40 and 782.20

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Solution

The fourth proportional to 1,212.28, 1,818.40 and 782.20 is: 1,173.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.28 : 1,818.40 = 782.20 : x
  2. Step 2: Convert to fraction form
    1,212.28/1,818.40 = 782.20/x
  3. Step 3: Cross multiply
    1,212.28x = 1,818.40 × 782.20
  4. Step 4: Simplify right side
    1,212.28x = 1,422,352.48
  5. Step 5: Solve for x
    x = 1,422,352.48/1,212.28
  6. Step 6: Final answer
    x = 1,173.29

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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.