Concept:To decide whether a triangle is right angled or acute angled, the given information must determine the angles or the relation among the sides.
Explanation:Statement (1) gives only the area,
140 cm2, and two sides
a and
b. The area is expressed as
21absinC=140. Since actual values of
a and
b are not known, this relation can hold for many different triangles, including acute, right, and obtuse triangles. So statement (1) alone is not sufficient.
Statement (2) says median
AD to side
BC equals altitude
AE to side
BC. Since
AE is the shortest distance from
A to the line
BC, equality forces
D and
E to be the same point. Hence
AD is the perpendicular bisector of
BC, giving
AB=AC. Thus the triangle is isosceles. But an isosceles triangle can be right angled or acute angled, depending on the apex angle. Statement (2) alone is not sufficient.
Combining both statements, the area condition and the isosceles condition still do not fix the actual side lengths or the angles. Therefore, additional data are needed.
Answer:Option D — Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data are needed.