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Finding the Fourth Proportional to 1,980, 2,969.64 and 1,286.19

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Solution

The fourth proportional to 1,980, 2,969.64 and 1,286.19 is: 1,929.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,980 : 2,969.64 = 1,286.19 : x
  2. Step 2: Convert to fraction form
    1,980/2,969.64 = 1,286.19/x
  3. Step 3: Cross multiply
    1,980x = 2,969.64 × 1,286.19
  4. Step 4: Simplify right side
    1,980x = 3,819,521.27
  5. Step 5: Solve for x
    x = 3,819,521.27/1,980
  6. Step 6: Final answer
    x = 1,929.05

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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.