https://www.khanacademy.org/math/geometry-home/triangle-properties/perpendicular-bisectors/v/three-points-defining-a-circle 2020-06-23T07:22:36Z Three points defining a circle Three points uniquely define a circle. If you circumscribe a circle around a triangle, the circumcenter of that triangle will also be the center of that circle. Sal Khan video https://cdn.kastatic.org/googleusercontent/xHTOWerq3bVTz9nfS2e-3UGE7JAflPi0BdIAgXmeEUhcWqRIsFnfUtEJdaewBYNptuVbnx-UkKp8YOcUgux03eq4 Three points defining a circle Three points uniquely define a circle. If you circumscribe a circle around a triangle, the circumcenter of that triangle will also be the center of that circle. https://cdn.kastatic.org/ka-youtube-converted/4_xhiP6g2ow.mp4/4_xhiP6g2ow.mp4 608 Circunferencia https://www.khanacademy.org/math/geometry-home/triangle-properties/angle-bisectors/v/inradius-perimeter-and-area 2021-04-19T14:43:38Z Inradius, perimeter, & area Showing that area is equal to inradius times semiperimeter Sal Khan video https://cdn.kastatic.org/googleusercontent/ZhmFlBAhD65qr5Uukxu_tviZVnF535RYSXvsikAaEtmA_G-tVseuVzDDy26K21M0DRdum8rhvnQ_pNFbW6Q-jL2G Inradius, perimeter, & area Showing that area is equal to inradius times semiperimeter https://cdn.kastatic.org/ka-youtube-converted/5NjgcPri07E.mp4/5NjgcPri07E.mp4 449 Circunferencia