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Two isosceles triangles are joined by making their bases coincide; when this is done

the sum of the lengths of the four sides plus the single "base" is 244 cm. If a
trapezoid is formed from one of the triangles by joining the midpoints of the
congruent sides with a segment that is parallel to the base, the perimeter of the
resulting trapezoid is 106 cm. What are the lengths of the sides and base of the
triangle?

1 Answer

4 votes

The provided system yields an invalid solution with
\(a = -138\), which is infeasible for side lengths. The problem likely contains an error or inconsistency in the given information.

denote the lengths of the congruent sides of each isosceles triangle as
\(a\) cm, and the base as
\(b\) cm.

Given:

The sum of the lengths of the four congruent sides and the single base is 244 cm:


\[2a + 2a + b = 244 \implies 4a + b = 244\]

Forming a trapezoid from one triangle by joining midpoints of the congruent sides with a segment parallel to the base results in a perimeter of 106 cm. In a trapezoid, the mid-segment is half the sum of the bases. Thus, the length of the base of the trapezoid (sum of the congruent sides of the triangle) is
\(2a\). So, the perimeter
\(106\) can be expressed as:


\[2a + 2a + a + b = 106 \implies 5a + b = 106\]

Now, let's solve this system of equations:

1.
\(4a + b = 244\)

2.
\(5a + b = 106\)

Subtracting equation 1 from equation 2 to eliminate \(b\):


\[ (5a + b) - (4a + b) = 106 - 244 \]


\[ a = -138 \]

This result for \(a\) seems invalid, indicating an inconsistency in the given information. A negative value for the length of a side of a triangle isn't feasible.

complete the question

"Two isosceles triangles have coinciding bases. The combined sum of their four congruent sides and a single base is 244 cm. Creating a trapezoid from one triangle by joining midpoints of the congruent sides with a segment parallel to the base results in a trapezoid with a perimeter of 106 cm. Find the lengths of the sides and the base of the triangles."

User Ron F
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