Instructional Video
Khan Academy

Khan Academy: Trig Word Problem: Stars

9th - 10th Standards
Sal solves a word problem about the distance between stars using the law of cosines.
Instructional Video
Khan Academy

Khan Academy: Solving for a Side With the Law of Cosines

9th - 10th Standards
Learn how to use the law of cosines to find the missing side length of a triangle when given two side lengths and the contained angle measure.
Instructional Video
Khan Academy

Khan Academy: Proof of the Law of Cosines

9th - 10th Standards
Sal gives a simple proof of the Law of cosines.
Instructional Video
Sophia Learning

Sophia: Coordinate Geometry of Parallelograms: Lesson 3

9th - 10th Standards
This lesson [7:43] will demonstrate how to use slope, midpoint, and distance formulas to determine from the coordinates of the vertices if a quadrilateral is a parallelogram in a coordinate plane. It is 3 of 6 in the series titled...
Instructional Video
Sophia Learning

Sophia: Coordinate Geometry of Trapezoids: Lesson 4

9th - 10th Standards
This lesson [15:33] will demonstrate how to use slope, midpoint, and distance formulas to determine, from the coordinates of the vertices of a quadrilateral, if the shape is a trapezoid. It is 4 of 4 in the series titled "Coordinate...
Instructional Video
Sophia Learning

Sophia: Coordinate Geometry of Trapezoids: Lesson 1

9th - 10th Standards
This lesson [5:14] will demonstrate how to use slope, midpoint, and distance formulas to determine, from the coordinates of the vertices, if a quadrilateral is a trapezoid in a coordinate plane. It is 1 of 4 in the series titled...
Instructional Video
Sophia Learning

Sophia: Coordinate Geometry of Rhombii: Lesson 2

9th - 10th Standards
This lesson [8:20] will demonstrate how to use slope, midpoint, and distance formulas to determine from the coordinates of the vertices if a quadrilateral is a rhombus in a coordinate plane. It is 2 of 4 in the series titled "Coordinate...