Question

justify the following:
an equilateral triangle is always an acute-angled triangle.

Answer 1

An equilateral triangle is always an acute-angled triangle because in equilateral triangle all angle have equal measure i.e. 60° which are less than 90° and hence acute angled triangle

Answer 2

yes
it cant be an obtuse because
91+91+91is greater than 180

it can't be a right angled because
90+90+90 is greater than 180

it can only be acute