sat-dog

Choice B is correct. The perimeter of a triangle is the sum of the lengths of all three of its sides. It’s given that the lengths of two sides of a triangle are 4 centimeters and 6 centimeters. Let x represent the length, in centimeters, of the third side of this triangle. The sum of the lengths, in centimeters, of all three 4+6+ sides of the triangle can be represented by the expression x. Since it’s 18 given that the perimeter of the triangle is centimeters, it follows that 4+6+ =18 10+ =18 10 x , or x . Subtracting from both sides of this equation = yields x 8. Therefore, the length, in centimeters, of the third side of this triangle is 8. Choice A is incorrect. If the length of the third side of this triangle were 4+6+2 2 centimeters, the perimeter, in centimeters, of the triangle would be , or 12 18 , not . Choice C is incorrect. If the length of the third side of this triangle were 10 4+6+10 centimeters, the perimeter, in centimeters, of the triangle would be , 20 18 or , not . Choice D is incorrect. If the length of the third side of this triangle 24 were centimeters, the perimeter, in centimeters, of the triangle would be 4+6+24 34 18 , or , not .