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Finding the Fourth Proportional to 1,611.40, 2,223.66 and 990.40

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Solution

The fourth proportional to 1,611.40, 2,223.66 and 990.40 is: 1,366.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,611.40 : 2,223.66 = 990.40 : x
  2. Step 2: Convert to fraction form
    1,611.40/2,223.66 = 990.40/x
  3. Step 3: Cross multiply
    1,611.40x = 2,223.66 × 990.40
  4. Step 4: Simplify right side
    1,611.40x = 2,202,312.86
  5. Step 5: Solve for x
    x = 2,202,312.86/1,611.40
  6. Step 6: Final answer
    x = 1,366.71

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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.