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Finding the Fourth Proportional to 1,981.90, 2,972.37 and 665.70

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Solution

The fourth proportional to 1,981.90, 2,972.37 and 665.70 is: 998.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,981.90 : 2,972.37 = 665.70 : x
  2. Step 2: Convert to fraction form
    1,981.90/2,972.37 = 665.70/x
  3. Step 3: Cross multiply
    1,981.90x = 2,972.37 × 665.70
  4. Step 4: Simplify right side
    1,981.90x = 1,978,706.71
  5. Step 5: Solve for x
    x = 1,978,706.71/1,981.90
  6. Step 6: Final answer
    x = 998.39

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1.5x scale

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.