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Finding the Fourth Proportional to 1,069.99, 1,605.21 and 420.79

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Solution

The fourth proportional to 1,069.99, 1,605.21 and 420.79 is: 631.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,069.99 : 1,605.21 = 420.79 : x
  2. Step 2: Convert to fraction form
    1,069.99/1,605.21 = 420.79/x
  3. Step 3: Cross multiply
    1,069.99x = 1,605.21 × 420.79
  4. Step 4: Simplify right side
    1,069.99x = 675,456.32
  5. Step 5: Solve for x
    x = 675,456.32/1,069.99
  6. Step 6: Final answer
    x = 631.27

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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.