0 votes 0 votes Four equilateral triangles are used to form a regular closed three-dimensional object by joining along the edges. The angle between any two faces is $30^{\circ}$ $60^{\circ}$ $45^{\circ}$ $90^{\circ}$ Others gateme-2024 + – admin asked Feb 16 • edited Feb 23 by makhdoom ghaya ♦admin 4.4k points answer See all 0 reply