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Finding the Fourth Proportional to 230, 345 and 85.72

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Solution

The fourth proportional to 230, 345 and 85.72 is: 128.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    230 : 345 = 85.72 : x
  2. Step 2: Convert to fraction form
    230/345 = 85.72/x
  3. Step 3: Cross multiply
    230x = 345 × 85.72
  4. Step 4: Simplify right side
    230x = 29,573.40
  5. Step 5: Solve for x
    x = 29,573.40/230
  6. Step 6: Final answer
    x = 128.58

Related Problems

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Double scale
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Similar ratio
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.