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Finding the Fourth Proportional to 210.21, 290.10 and 121.70

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Solution

The fourth proportional to 210.21, 290.10 and 121.70 is: 167.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.21 : 290.10 = 121.70 : x
  2. Step 2: Convert to fraction form
    210.21/290.10 = 121.70/x
  3. Step 3: Cross multiply
    210.21x = 290.10 × 121.70
  4. Step 4: Simplify right side
    210.21x = 35,305.17
  5. Step 5: Solve for x
    x = 35,305.17/210.21
  6. Step 6: Final answer
    x = 167.95

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.