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Finding the Fourth Proportional to 1,139.40, 1,709.28 and 490.14

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Solution

The fourth proportional to 1,139.40, 1,709.28 and 490.14 is: 735.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.40 : 1,709.28 = 490.14 : x
  2. Step 2: Convert to fraction form
    1,139.40/1,709.28 = 490.14/x
  3. Step 3: Cross multiply
    1,139.40x = 1,709.28 × 490.14
  4. Step 4: Simplify right side
    1,139.40x = 837,786.50
  5. Step 5: Solve for x
    x = 837,786.50/1,139.40
  6. Step 6: Final answer
    x = 735.29

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Double scale
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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.