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Finding the Fourth Proportional to 6.64, 9.15 and 4.21

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Solution

The fourth proportional to 6.64, 9.15 and 4.21 is: 5.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.64 : 9.15 = 4.21 : x
  2. Step 2: Convert to fraction form
    6.64/9.15 = 4.21/x
  3. Step 3: Cross multiply
    6.64x = 9.15 × 4.21
  4. Step 4: Simplify right side
    6.64x = 38.50
  5. Step 5: Solve for x
    x = 38.50/6.64
  6. Step 6: Final answer
    x = 5.80

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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.