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Finding the Fourth Proportional to 1,211.40, 1,817.22 and 389.64

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Solution

The fourth proportional to 1,211.40, 1,817.22 and 389.64 is: 584.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,211.40 : 1,817.22 = 389.64 : x
  2. Step 2: Convert to fraction form
    1,211.40/1,817.22 = 389.64/x
  3. Step 3: Cross multiply
    1,211.40x = 1,817.22 × 389.64
  4. Step 4: Simplify right side
    1,211.40x = 708,061.60
  5. Step 5: Solve for x
    x = 708,061.60/1,211.40
  6. Step 6: Final answer
    x = 584.50

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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.