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Finding the Fourth Proportional to 1,120, 1,679.60 and 426.86

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Solution

The fourth proportional to 1,120, 1,679.60 and 426.86 is: 640.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,120 : 1,679.60 = 426.86 : x
  2. Step 2: Convert to fraction form
    1,120/1,679.60 = 426.86/x
  3. Step 3: Cross multiply
    1,120x = 1,679.60 × 426.86
  4. Step 4: Simplify right side
    1,120x = 716,954.06
  5. Step 5: Solve for x
    x = 716,954.06/1,120
  6. Step 6: Final answer
    x = 640.14

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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.