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Finding the Fourth Proportional to 56.81, 85.15 and 20.70

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Solution

The fourth proportional to 56.81, 85.15 and 20.70 is: 31.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.81 : 85.15 = 20.70 : x
  2. Step 2: Convert to fraction form
    56.81/85.15 = 20.70/x
  3. Step 3: Cross multiply
    56.81x = 85.15 × 20.70
  4. Step 4: Simplify right side
    56.81x = 1,762.61
  5. Step 5: Solve for x
    x = 1,762.61/56.81
  6. Step 6: Final answer
    x = 31.03

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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.