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Finding the Fourth Proportional to 1,219.38, 1,682.61 and 688.21

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Solution

The fourth proportional to 1,219.38, 1,682.61 and 688.21 is: 949.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,219.38 : 1,682.61 = 688.21 : x
  2. Step 2: Convert to fraction form
    1,219.38/1,682.61 = 688.21/x
  3. Step 3: Cross multiply
    1,219.38x = 1,682.61 × 688.21
  4. Step 4: Simplify right side
    1,219.38x = 1,157,995.58
  5. Step 5: Solve for x
    x = 1,157,995.58/1,219.38
  6. Step 6: Final answer
    x = 949.66

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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.