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Finding the Fourth Proportional to 30.30, 42.02 and 28.77

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Solution

The fourth proportional to 30.30, 42.02 and 28.77 is: 39.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.30 : 42.02 = 28.77 : x
  2. Step 2: Convert to fraction form
    30.30/42.02 = 28.77/x
  3. Step 3: Cross multiply
    30.30x = 42.02 × 28.77
  4. Step 4: Simplify right side
    30.30x = 1,208.92
  5. Step 5: Solve for x
    x = 1,208.92/30.30
  6. Step 6: Final answer
    x = 39.90

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Find fourth proportional to 15.15, 21.01 and 14.39
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.