You know it's an obtuse triangle when one of the angles is greater than 90 degress, and both of the others are less than 90 degrees.
Nnukwu nkuku, nwere triangle nke akụkụ ya abụọ nwere nnukwu akụkụ, ya bụ, ihe na-erughị ogo 90, (na nke a kwa triangle ziri ezi bụkwa rectangle ebe akụkụ ya abụọ nwere ihe na-erughị ogo 90.