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Finding the Fourth Proportional to 123.65, 170.19 and 86.75

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Solution

The fourth proportional to 123.65, 170.19 and 86.75 is: 119.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.65 : 170.19 = 86.75 : x
  2. Step 2: Convert to fraction form
    123.65/170.19 = 86.75/x
  3. Step 3: Cross multiply
    123.65x = 170.19 × 86.75
  4. Step 4: Simplify right side
    123.65x = 14,763.72
  5. Step 5: Solve for x
    x = 14,763.72/123.65
  6. Step 6: Final answer
    x = 119.40

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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.