Isosceles triangle from symbolic perimeter: The base of an isosceles triangle is B = 2x + 2y + 4z and the perimeter is P = 4x + 2y + 6z (expressions in the same units). Find the length of each equal side.
-
Ax+y
-
Bx+y+z
-
C2(x+y)
-
Dx+z
-
ENone of these
Answer
Correct Answer: x+z
Explanation
Introduction / Context:For an isosceles triangle with base B and equal sides s, perimeter P satisfies P = B + 2s. Rearranging gives s = (P − B)/2. Here B and P are algebraic expressions in x, y, z that represent like units (e.g., centimetres).
Given Data / Assumptions:
- Base B = 2x + 2y + 4z.
- Perimeter P = 4x + 2y + 6z.
- All symbols represent nonnegative measures in the same unit.
Concept / Approach:Apply s = (P − B)/2 algebraically and simplify the expression; this yields the length of each congruent side in terms of x and z only, since the y-terms cancel here.
Step-by-Step Solution:
P − B = (4x + 2y + 6z) − (2x + 2y + 4z) = 2x + 2z.s = (P − B)/2 = (2x + 2z)/2 = x + z.Verification / Alternative check:Perimeter re-formed: B + 2s = (2x + 2y + 4z) + 2(x + z) = 4x + 2y + 6z = P, consistent.
Why Other Options Are Wrong:Options involving y do not reflect the cancellation; 2(x + y) doubles the wrong combination; x + y is not supported by P − B reduction.
Common Pitfalls:Forgetting the factor 1/2 in s = (P − B)/2; algebraic sign mistakes.
Final Answer:x+z