What type of triangle has sides of 25cm and 87cm?

Answer 1

It could be acute, right angled, obtuse and

scalene or isosceles (unless it is right angled).

Which depends upon the length of the third side (which must be between 62 cm and 112 cm exclusive):

• If the third side is greater than 62 cm and less than √6944 (≈ 83.331) cm, or greater than √8194 (≈ 90.521) cm and less than 112 cm then it is an obtuse scalene triangle.
• If the third side is greater than √6944 (≈ 83.331) cm and less than 87 cm, or greater than 87cm and less than √8194 (≈ 90.521) cm then it is an acute scalene triangle
• If the third side equals √6944 (≈ 83.331) cm or √8194 (≈ 90.521) cm then it is a right angled triangle
• If the third side equals 87 cm then it is an acute isosceles triangle.

Answer 2

It can be an acute angled, right angled or obtuse angled triangle. Except in the case of a right angled triangle, it can be isosceles or scalene.