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Finding the Fourth Proportional to 30.42, 45.60 and 21.45

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Solution

The fourth proportional to 30.42, 45.60 and 21.45 is: 32.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.42 : 45.60 = 21.45 : x
  2. Step 2: Convert to fraction form
    30.42/45.60 = 21.45/x
  3. Step 3: Cross multiply
    30.42x = 45.60 × 21.45
  4. Step 4: Simplify right side
    30.42x = 978.12
  5. Step 5: Solve for x
    x = 978.12/30.42
  6. Step 6: Final answer
    x = 32.15

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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.