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Finding the Fourth Proportional to 1,394.89, 2,091.69 and 420.80

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Solution

The fourth proportional to 1,394.89, 2,091.69 and 420.80 is: 631.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,394.89 : 2,091.69 = 420.80 : x
  2. Step 2: Convert to fraction form
    1,394.89/2,091.69 = 420.80/x
  3. Step 3: Cross multiply
    1,394.89x = 2,091.69 × 420.80
  4. Step 4: Simplify right side
    1,394.89x = 880,172.69
  5. Step 5: Solve for x
    x = 880,172.69/1,394.89
  6. Step 6: Final answer
    x = 631.00

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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.