Question

It is impossible for a triangle to be which of the following?

a. both isosceles and right
b. both equilateral and equiangular
c. both scalene and acute
d. both obtuse and equliateral

Answer 1

d will be the answer

Answer 2

ans: d

Answer 3

if it is equilateral then each angle is same and equal to 180/3=60. so it can't be obtuse.
so ans :d

Answer 4

Ans: D

Answer 5

d:
what i mean below is referring to an obtuse triangle
the reason is that an obtuse angle means an angle which is always greater than 90deg.
refering to angle sum of triangle, any one of the other two angle must be smaller than 90deg. this implies that the side opposite to the obtuse angle is greater than the other two sides by "greater angle, greater side" (see Euclid's Elements)