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Finding the Fourth Proportional to 153.80, 211.90 and 120.99

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Solution

The fourth proportional to 153.80, 211.90 and 120.99 is: 166.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.80 : 211.90 = 120.99 : x
  2. Step 2: Convert to fraction form
    153.80/211.90 = 120.99/x
  3. Step 3: Cross multiply
    153.80x = 211.90 × 120.99
  4. Step 4: Simplify right side
    153.80x = 25,637.18
  5. Step 5: Solve for x
    x = 25,637.18/153.80
  6. Step 6: Final answer
    x = 166.70

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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.