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Finding the Fourth Proportional to 409, 613.50 and 105

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Solution

The fourth proportional to 409, 613.50 and 105 is: 157.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    409 : 613.50 = 105 : x
  2. Step 2: Convert to fraction form
    409/613.50 = 105/x
  3. Step 3: Cross multiply
    409x = 613.50 × 105
  4. Step 4: Simplify right side
    409x = 64,417.50
  5. Step 5: Solve for x
    x = 64,417.50/409
  6. Step 6: Final answer
    x = 157.50

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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.