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Finding the Fourth Proportional to 129.12, 178 and 85.52

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Solution

The fourth proportional to 129.12, 178 and 85.52 is: 117.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.12 : 178 = 85.52 : x
  2. Step 2: Convert to fraction form
    129.12/178 = 85.52/x
  3. Step 3: Cross multiply
    129.12x = 178 × 85.52
  4. Step 4: Simplify right side
    129.12x = 15,222.56
  5. Step 5: Solve for x
    x = 15,222.56/129.12
  6. Step 6: Final answer
    x = 117.89

Related Problems

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1.5x scale

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.