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Finding the Fourth Proportional to 1,981.40, 2,971.62 and 665.20

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Solution

The fourth proportional to 1,981.40, 2,971.62 and 665.20 is: 997.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,981.40 : 2,971.62 = 665.20 : x
  2. Step 2: Convert to fraction form
    1,981.40/2,971.62 = 665.20/x
  3. Step 3: Cross multiply
    1,981.40x = 2,971.62 × 665.20
  4. Step 4: Simplify right side
    1,981.40x = 1,976,723.29
  5. Step 5: Solve for x
    x = 1,976,723.29/1,981.40
  6. Step 6: Final answer
    x = 997.64

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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.