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Finding the Fourth Proportional to 313.20, 469.38 and 139.80

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Solution

The fourth proportional to 313.20, 469.38 and 139.80 is: 209.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    313.20 : 469.38 = 139.80 : x
  2. Step 2: Convert to fraction form
    313.20/469.38 = 139.80/x
  3. Step 3: Cross multiply
    313.20x = 469.38 × 139.80
  4. Step 4: Simplify right side
    313.20x = 65,619.32
  5. Step 5: Solve for x
    x = 65,619.32/313.20
  6. Step 6: Final answer
    x = 209.51

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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.