أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
<p><strong><a>A.</a></strong> <strong>ground level and springing line</strong> <strong><a>B.</a></strong> <strong>crown and springing line</strong> <strong><a>C.</a></strong> <strong>crown and ground level</strong> <strong><a>D.</a></strong> <strong>intrados and extrados.</strong></p> <p> </p>
The sagitta is the height of an arc. It is the perpendicular from the midpoint of the arc's chord to the arc itself. 
Thank you for the invitation
He agreed with the colleagues' answers
I believe the best choice is answer "D" intrados and extrados.
The depth of an arch is the distance between intrados and extrados.
