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Finding the Fourth Proportional to 291.14, 436.76 and 85.70

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Solution

The fourth proportional to 291.14, 436.76 and 85.70 is: 128.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.14 : 436.76 = 85.70 : x
  2. Step 2: Convert to fraction form
    291.14/436.76 = 85.70/x
  3. Step 3: Cross multiply
    291.14x = 436.76 × 85.70
  4. Step 4: Simplify right side
    291.14x = 37,427.72
  5. Step 5: Solve for x
    x = 37,427.72/291.14
  6. Step 6: Final answer
    x = 128.56

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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.