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Finding the Fourth Proportional to 30.75, 42.42 and 21.52

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Solution

The fourth proportional to 30.75, 42.42 and 21.52 is: 29.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.75 : 42.42 = 21.52 : x
  2. Step 2: Convert to fraction form
    30.75/42.42 = 21.52/x
  3. Step 3: Cross multiply
    30.75x = 42.42 × 21.52
  4. Step 4: Simplify right side
    30.75x = 912.88
  5. Step 5: Solve for x
    x = 912.88/30.75
  6. Step 6: Final answer
    x = 29.69

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Find fourth proportional to 15.38, 21.21 and 10.76
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1.5x scale

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.