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Finding the Fourth Proportional to 291.05, 436.40 and 128.55

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Solution

The fourth proportional to 291.05, 436.40 and 128.55 is: 192.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.05 : 436.40 = 128.55 : x
  2. Step 2: Convert to fraction form
    291.05/436.40 = 128.55/x
  3. Step 3: Cross multiply
    291.05x = 436.40 × 128.55
  4. Step 4: Simplify right side
    291.05x = 56,098.58
  5. Step 5: Solve for x
    x = 56,098.58/291.05
  6. Step 6: Final answer
    x = 192.75

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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.