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Finding the Fourth Proportional to 1,321.20, 1,981.32 and 671.82

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Solution

The fourth proportional to 1,321.20, 1,981.32 and 671.82 is: 1,007.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,321.20 : 1,981.32 = 671.82 : x
  2. Step 2: Convert to fraction form
    1,321.20/1,981.32 = 671.82/x
  3. Step 3: Cross multiply
    1,321.20x = 1,981.32 × 671.82
  4. Step 4: Simplify right side
    1,321.20x = 1,331,090.40
  5. Step 5: Solve for x
    x = 1,331,090.40/1,321.20
  6. Step 6: Final answer
    x = 1,007.49

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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.