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Finding the Fourth Proportional to 51.68, 71.20 and 40.80

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Solution

The fourth proportional to 51.68, 71.20 and 40.80 is: 56.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.68 : 71.20 = 40.80 : x
  2. Step 2: Convert to fraction form
    51.68/71.20 = 40.80/x
  3. Step 3: Cross multiply
    51.68x = 71.20 × 40.80
  4. Step 4: Simplify right side
    51.68x = 2,904.96
  5. Step 5: Solve for x
    x = 2,904.96/51.68
  6. Step 6: Final answer
    x = 56.21

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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.