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Finding the Fourth Proportional to 5.40, 7.45 and 4.20

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Solution

The fourth proportional to 5.40, 7.45 and 4.20 is: 5.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    5.40 : 7.45 = 4.20 : x
  2. Step 2: Convert to fraction form
    5.40/7.45 = 4.20/x
  3. Step 3: Cross multiply
    5.40x = 7.45 × 4.20
  4. Step 4: Simplify right side
    5.40x = 31.29
  5. Step 5: Solve for x
    x = 31.29/5.40
  6. Step 6: Final answer
    x = 5.79

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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.