The Triangle Inequality Theorem states that for any three sides of a triangle (a, b, c), the following conditions must be satisfied:
- \( a + b > c \)
- \( a + c > b \)
- \( b + c > a \)
Let's evaluate each set of side lengths:
-
10, 20, 15:
- \( 10 + 20 = 30 > 15 \) (True)
- \( 10 + 15 = 25 > 20 \) (True)
- \( 20 + 15 = 35 > 10 \) (True)
- These can form a triangle.
-
8, 4, 12:
- \( 8 + 4 = 12 \) (Not greater than)
- \( 8 + 12 = 20 > 4 \) (True)
- \( 4 + 12 = 16 > 8 \) (True)
- These cannot form a triangle.
-
20, 10, 30:
- \( 20 + 10 = 30 \) (Not greater than)
- \( 20 + 30 = 50 > 10 \) (True)
- \( 10 + 30 = 40 > 20 \) (True)
- These cannot form a triangle.
-
8, 8, 20:
- \( 8 + 8 = 16 < 20 \) (Not greater than)
- \( 8 + 20 = 28 > 8 \) (True)
- \( 8 + 20 = 28 > 8 \) (True)
- These cannot form a triangle.
The only set of sides that can form a triangle is 10, 20, 15.