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Finding the Fourth Proportional to 94.80, 130.76 and 78.40

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Solution

The fourth proportional to 94.80, 130.76 and 78.40 is: 108.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    94.80 : 130.76 = 78.40 : x
  2. Step 2: Convert to fraction form
    94.80/130.76 = 78.40/x
  3. Step 3: Cross multiply
    94.80x = 130.76 × 78.40
  4. Step 4: Simplify right side
    94.80x = 10,251.58
  5. Step 5: Solve for x
    x = 10,251.58/94.80
  6. Step 6: Final answer
    x = 108.14

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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.