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Finding the Fourth Proportional to 56.80, 78.20 and 54.40

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Solution

The fourth proportional to 56.80, 78.20 and 54.40 is: 74.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.80 : 78.20 = 54.40 : x
  2. Step 2: Convert to fraction form
    56.80/78.20 = 54.40/x
  3. Step 3: Cross multiply
    56.80x = 78.20 × 54.40
  4. Step 4: Simplify right side
    56.80x = 4,254.08
  5. Step 5: Solve for x
    x = 4,254.08/56.80
  6. Step 6: Final answer
    x = 74.90

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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.