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Finding the Fourth Proportional to 78.04, 115.40 and 77.84

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Solution

The fourth proportional to 78.04, 115.40 and 77.84 is: 115.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.04 : 115.40 = 77.84 : x
  2. Step 2: Convert to fraction form
    78.04/115.40 = 77.84/x
  3. Step 3: Cross multiply
    78.04x = 115.40 × 77.84
  4. Step 4: Simplify right side
    78.04x = 8,982.74
  5. Step 5: Solve for x
    x = 8,982.74/78.04
  6. Step 6: Final answer
    x = 115.10

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Why These Related Problems?

These problems maintain the same ratio (1.48) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.