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Finding the Fourth Proportional to 210.40, 290.36 and 121.91

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Solution

The fourth proportional to 210.40, 290.36 and 121.91 is: 168.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.40 : 290.36 = 121.91 : x
  2. Step 2: Convert to fraction form
    210.40/290.36 = 121.91/x
  3. Step 3: Cross multiply
    210.40x = 290.36 × 121.91
  4. Step 4: Simplify right side
    210.40x = 35,396.34
  5. Step 5: Solve for x
    x = 35,396.34/210.40
  6. Step 6: Final answer
    x = 168.24

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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.