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Finding the Fourth Proportional to 981.56, 1,354.20 and 667.80

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Solution

The fourth proportional to 981.56, 1,354.20 and 667.80 is: 921.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.56 : 1,354.20 = 667.80 : x
  2. Step 2: Convert to fraction form
    981.56/1,354.20 = 667.80/x
  3. Step 3: Cross multiply
    981.56x = 1,354.20 × 667.80
  4. Step 4: Simplify right side
    981.56x = 904,334.76
  5. Step 5: Solve for x
    x = 904,334.76/981.56
  6. Step 6: Final answer
    x = 921.32

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1.5x scale

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.