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Finding the Fourth Proportional to 82.16, 123.76 and 78.80

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Solution

The fourth proportional to 82.16, 123.76 and 78.80 is: 118.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.16 : 123.76 = 78.80 : x
  2. Step 2: Convert to fraction form
    82.16/123.76 = 78.80/x
  3. Step 3: Cross multiply
    82.16x = 123.76 × 78.80
  4. Step 4: Simplify right side
    82.16x = 9,752.29
  5. Step 5: Solve for x
    x = 9,752.29/82.16
  6. Step 6: Final answer
    x = 118.70

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.