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Finding the Fourth Proportional to 78.04, 107.76 and 57.40

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Solution

The fourth proportional to 78.04, 107.76 and 57.40 is: 79.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.04 : 107.76 = 57.40 : x
  2. Step 2: Convert to fraction form
    78.04/107.76 = 57.40/x
  3. Step 3: Cross multiply
    78.04x = 107.76 × 57.40
  4. Step 4: Simplify right side
    78.04x = 6,185.42
  5. Step 5: Solve for x
    x = 6,185.42/78.04
  6. Step 6: Final answer
    x = 79.26

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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.