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Finding the Fourth Proportional to 1,105, 1,657.50 and 421.16

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Solution

The fourth proportional to 1,105, 1,657.50 and 421.16 is: 631.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,105 : 1,657.50 = 421.16 : x
  2. Step 2: Convert to fraction form
    1,105/1,657.50 = 421.16/x
  3. Step 3: Cross multiply
    1,105x = 1,657.50 × 421.16
  4. Step 4: Simplify right side
    1,105x = 698,072.70
  5. Step 5: Solve for x
    x = 698,072.70/1,105
  6. Step 6: Final answer
    x = 631.74

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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.