diff --git a/Intersections_3/test/Intersections_3/triangle_3_triangle_3_intersection.cpp b/Intersections_3/test/Intersections_3/triangle_3_triangle_3_intersection.cpp
index 0098bcd0142..f0875a55ee8 100644
--- a/Intersections_3/test/Intersections_3/triangle_3_triangle_3_intersection.cpp
+++ b/Intersections_3/test/Intersections_3/triangle_3_triangle_3_intersection.cpp
@@ -96,6 +96,13 @@ void test_coplanar_triangles(){
   assert(CGAL::object_cast<Triangle>(&obj)!=nullptr);
   obj=CGAL::intersection(t2,t1);
   assert(CGAL::object_cast<Triangle>(&obj)!=nullptr);
+  // TK10 case C'
+  t1=Triangle(Point(88.7921, 89.0007, 1.25), Point(88.1912, 88.3997, 1.25), Point(89.8224, 90.031, 1.25));
+  t2=Triangle(Point(88.0497, 88.2583, 1.25), Point(82.9292, 81.8747, 1.25), Point(91.1726, 91.3812, 1.25));
+  obj=CGAL::intersection(t1,t2);
+  assert(CGAL::object_cast<Triangle>(&obj)!=nullptr);
+  obj=CGAL::intersection(t2,t1);
+  assert(CGAL::object_cast<Triangle>(&obj)!=nullptr);
 //Intersection is a point
   //edges  are collinear, one vertex in common
   t1=Triangle( Point(0,0,0),Point(0,1,0),Point(1,0,0) );
@@ -153,6 +160,13 @@ void test_coplanar_triangles(){
   assert(CGAL::object_cast<Segment>(&obj)!=nullptr);
   obj=CGAL::intersection(t2,t1);
   assert(CGAL::object_cast<Segment>(&obj)!=nullptr);
+  // TK10 case D
+  t1=Triangle(Point(-34.893700000000003, -16.0351, 3.1334899999999998e-12), Point(-34.893700000000003, -18.5351, 3.1334899999999998e-12), Point(-42.393700000000003, -16.0351, 3.1334899999999998e-12));
+  t2=Triangle(Point(-34.893700000000003, -32.0351, 3.1334899999999998e-12), Point(-34.893700000000003, -9.7851400000000002, 3.1334899999999998e-12), Point(-31.643699999999999, -17.201799999999999, 3.1334899999999998e-12));
+  obj=CGAL::intersection(t1,t2);
+  assert(CGAL::object_cast<Segment>(&obj)!=nullptr);
+  obj=CGAL::intersection(t2,t1);
+  assert(CGAL::object_cast<Segment>(&obj)!=nullptr);
 //Intersection is a polygon
   //David's star
   t1=Triangle( Point(0,0,0),Point(1,0,0),Point(0.5,1.5,0) );
@@ -181,6 +195,51 @@ void test_coplanar_triangles(){
   obj=CGAL::intersection(t2,t1);
   assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
   assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  // TK10 case A
+  t1=Triangle(Point(3.74861, 12.4822, 14.0112), Point(5.40582, 12.4822, 15.6895), Point(5.37748, 12.4822, 15.7206));
+  t2=Triangle(Point(5.49972, 12.4822, 13.491), Point(5.27627, 12.4822, 15.8106), Point(5.32119, 12.4822, 15.8126));
+  obj=CGAL::intersection(t1,t2);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  obj=CGAL::intersection(t2,t1);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  // TK10 case C
+  t1=Triangle(Point(5, -94.6659, 3.85175), Point(5, -94.5682, 3.08638), Point(5, -94.8182, 3.08638));
+  t2=Triangle(Point(5, -94.4317, 3.76399), Point(5, -97.6182, 3.08638), Point(5, -94.5659, 2.99682));
+  obj=CGAL::intersection(t1,t2);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  obj=CGAL::intersection(t2,t1);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  // TK10 case E
+  t1=Triangle(Point(-955.858, -45.032, -0.016), Point(-955.856, -45.032, -0.004), Point(-955.856, -45.032, -0.002));
+  t2=Triangle(Point(-955.856, -45.032, 0.006), Point(-955.854, -45.032, -0.002), Point(-955.876, -45.032, -0.034));
+  obj=CGAL::intersection(t1,t2);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  obj=CGAL::intersection(t2,t1);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  // TK10 case F
+  t1=Triangle(Point(141.172, 20.576, 155.764), Point(141.172, 20.588, 155.766), Point(141.172, 20.59, 155.766));
+  t2=Triangle(Point(141.172, 20.602, 155.768), Point(141.172, 20.594, 155.766), Point(141.172, 20.574, 155.764));
+  obj=CGAL::intersection(t1,t2);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  obj=CGAL::intersection(t2,t1);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  // TK10 case D
+  t1=Triangle(Point(152.864, 126.324, 0.950001), Point(152.77, 126.483, 0.950001), Point(153.072, 125.973, 0.950001));
+  t2=Triangle(Point(153.322, 125.551, 0.950001), Point(152.218, 127.415, 0.950001), Point(153.66, 124.768, 0.950001));
+  obj=CGAL::intersection(t1,t2);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
+  obj=CGAL::intersection(t2,t1);
+  assert(CGAL::object_cast<Polygon2>(&obj)!=nullptr);
+  assert(CGAL::object_cast<Polygon2>(&obj)->size()==4);
 //Intersection is empty
   t1=Triangle( Point(0,0,0),Point(0,1,0),Point(1,0,0) );
   t2=Triangle( Point(-0.1,-0.1,0),Point(-0.1,-0.9,0),Point(-1,-0.1,0) );