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Finding the Fourth Proportional to 123.66, 170.81 and 87

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Solution

The fourth proportional to 123.66, 170.81 and 87 is: 120.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.66 : 170.81 = 87 : x
  2. Step 2: Convert to fraction form
    123.66/170.81 = 87/x
  3. Step 3: Cross multiply
    123.66x = 170.81 × 87
  4. Step 4: Simplify right side
    123.66x = 14,860.04
  5. Step 5: Solve for x
    x = 14,860.04/123.66
  6. Step 6: Final answer
    x = 120.17

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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.