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Finding the Fourth Proportional to 1,139.21, 1,707.95 and 445.78

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Solution

The fourth proportional to 1,139.21, 1,707.95 and 445.78 is: 668.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.21 : 1,707.95 = 445.78 : x
  2. Step 2: Convert to fraction form
    1,139.21/1,707.95 = 445.78/x
  3. Step 3: Cross multiply
    1,139.21x = 1,707.95 × 445.78
  4. Step 4: Simplify right side
    1,139.21x = 761,359.18
  5. Step 5: Solve for x
    x = 761,359.18/1,139.21
  6. Step 6: Final answer
    x = 668.32

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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.