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Finding the Fourth Proportional to 1,645, 2,269.20 and 981.40

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Solution

The fourth proportional to 1,645, 2,269.20 and 981.40 is: 1,353.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,645 : 2,269.20 = 981.40 : x
  2. Step 2: Convert to fraction form
    1,645/2,269.20 = 981.40/x
  3. Step 3: Cross multiply
    1,645x = 2,269.20 × 981.40
  4. Step 4: Simplify right side
    1,645x = 2,226,992.88
  5. Step 5: Solve for x
    x = 2,226,992.88/1,645
  6. Step 6: Final answer
    x = 1,353.80

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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.