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Finding the Fourth Proportional to 82.40, 113.76 and 56.21

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Solution

The fourth proportional to 82.40, 113.76 and 56.21 is: 77.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.40 : 113.76 = 56.21 : x
  2. Step 2: Convert to fraction form
    82.40/113.76 = 56.21/x
  3. Step 3: Cross multiply
    82.40x = 113.76 × 56.21
  4. Step 4: Simplify right side
    82.40x = 6,393.88
  5. Step 5: Solve for x
    x = 6,393.88/82.40
  6. Step 6: Final answer
    x = 77.60

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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.