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Finding the Fourth Proportional to 313, 469.20 and 139.72

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Solution

The fourth proportional to 313, 469.20 and 139.72 is: 209.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    313 : 469.20 = 139.72 : x
  2. Step 2: Convert to fraction form
    313/469.20 = 139.72/x
  3. Step 3: Cross multiply
    313x = 469.20 × 139.72
  4. Step 4: Simplify right side
    313x = 65,556.62
  5. Step 5: Solve for x
    x = 65,556.62/313
  6. Step 6: Final answer
    x = 209.45

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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.