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Finding the Fourth Proportional to 210.99, 316.57 and 81.05

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Solution

The fourth proportional to 210.99, 316.57 and 81.05 is: 121.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    210.99 : 316.57 = 81.05 : x
  2. Step 2: Convert to fraction form
    210.99/316.57 = 81.05/x
  3. Step 3: Cross multiply
    210.99x = 316.57 × 81.05
  4. Step 4: Simplify right side
    210.99x = 25,656.42
  5. Step 5: Solve for x
    x = 25,656.42/210.99
  6. Step 6: Final answer
    x = 121.60

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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.