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Finding the Fourth Proportional to 123.79, 170.89 and 84.65

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Solution

The fourth proportional to 123.79, 170.89 and 84.65 is: 116.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.79 : 170.89 = 84.65 : x
  2. Step 2: Convert to fraction form
    123.79/170.89 = 84.65/x
  3. Step 3: Cross multiply
    123.79x = 170.89 × 84.65
  4. Step 4: Simplify right side
    123.79x = 14,465.63
  5. Step 5: Solve for x
    x = 14,465.63/123.79
  6. Step 6: Final answer
    x = 116.86

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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.