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Finding the Fourth Proportional to 1,289.36, 1,921.36 and 1,211.45

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Solution

The fourth proportional to 1,289.36, 1,921.36 and 1,211.45 is: 1,805.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.36 : 1,921.36 = 1,211.45 : x
  2. Step 2: Convert to fraction form
    1,289.36/1,921.36 = 1,211.45/x
  3. Step 3: Cross multiply
    1,289.36x = 1,921.36 × 1,211.45
  4. Step 4: Simplify right side
    1,289.36x = 2,327,618.94
  5. Step 5: Solve for x
    x = 2,327,618.94/1,289.36
  6. Step 6: Final answer
    x = 1,805.25

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.