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Finding the Fourth Proportional to 391.55, 538.69 and 389.73

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Solution

The fourth proportional to 391.55, 538.69 and 389.73 is: 536.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.55 : 538.69 = 389.73 : x
  2. Step 2: Convert to fraction form
    391.55/538.69 = 389.73/x
  3. Step 3: Cross multiply
    391.55x = 538.69 × 389.73
  4. Step 4: Simplify right side
    391.55x = 209,941.71
  5. Step 5: Solve for x
    x = 209,941.71/391.55
  6. Step 6: Final answer
    x = 536.18

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.