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Finding the Fourth Proportional to 5.16, 7.75 and 1.78

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Solution

The fourth proportional to 5.16, 7.75 and 1.78 is: 2.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    5.16 : 7.75 = 1.78 : x
  2. Step 2: Convert to fraction form
    5.16/7.75 = 1.78/x
  3. Step 3: Cross multiply
    5.16x = 7.75 × 1.78
  4. Step 4: Simplify right side
    5.16x = 13.80
  5. Step 5: Solve for x
    x = 13.80/5.16
  6. Step 6: Final answer
    x = 2.67

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.