Carcass wrote:
A triangle has sides measuring 7 cm and 12 cm. Which of the following are possible values for the perimeter of the triangle?
Indicate all possible values.
A. 22 cm
B. 24 cm
C. 26 cm
D. 28 cm
E. 30 cm
F. 34 cm
G. 38 cm
IMPORTANT RULE: If two sides of a triangle have lengths A and B, then . . .
DIFFERENCE between A and B < length of third side < SUM of A and BSince the two known sides have lengths 7 and 12, we can write:
12 - 7 < length of third side < 12 + 7Simplify to get:
5 < length of third side < 19IF the length of the third side were 5, then the perimeter would equal 7 + 12 + 5 = 24
However, since the length of the third side must be
greater than 5, the perimeter must be
greater than 24
Likewise,
IF the length of the third side were 19, then the perimeter would equal 7 + 12 + 19 = 38
However, since the length of the third side must be
less than 5, the perimeter must be
less than 38
When we combine both pieces of information we get: 24 < perimeter < 38
The answer choices that work with us in equality are C, D, E and F
Answer: C, D, E, F