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Finding the Fourth Proportional to 123.84, 170.88 and 76.56

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Solution

The fourth proportional to 123.84, 170.88 and 76.56 is: 105.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.84 : 170.88 = 76.56 : x
  2. Step 2: Convert to fraction form
    123.84/170.88 = 76.56/x
  3. Step 3: Cross multiply
    123.84x = 170.88 × 76.56
  4. Step 4: Simplify right side
    123.84x = 13,082.57
  5. Step 5: Solve for x
    x = 13,082.57/123.84
  6. Step 6: Final answer
    x = 105.64

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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.