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Finding the Fourth Proportional to 57.10, 78.80 and 40.76

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Solution

The fourth proportional to 57.10, 78.80 and 40.76 is: 56.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.10 : 78.80 = 40.76 : x
  2. Step 2: Convert to fraction form
    57.10/78.80 = 40.76/x
  3. Step 3: Cross multiply
    57.10x = 78.80 × 40.76
  4. Step 4: Simplify right side
    57.10x = 3,211.89
  5. Step 5: Solve for x
    x = 3,211.89/57.10
  6. Step 6: Final answer
    x = 56.25

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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.