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Finding the Fourth Proportional to 129.32, 178.40 and 76.84

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Solution

The fourth proportional to 129.32, 178.40 and 76.84 is: 106.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.32 : 178.40 = 76.84 : x
  2. Step 2: Convert to fraction form
    129.32/178.40 = 76.84/x
  3. Step 3: Cross multiply
    129.32x = 178.40 × 76.84
  4. Step 4: Simplify right side
    129.32x = 13,708.26
  5. Step 5: Solve for x
    x = 13,708.26/129.32
  6. Step 6: Final answer
    x = 106.00

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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.