Look at adding an identical bulb to a circuit of a cell and a bulb. In this circuit the two light bulbs are in parallel to each other.

In this circuit the two light bulbs on the far right are in series with each other. The light bulb in the middle is in parallel to the other two light bulbs.

This video tutorial introduces skew lines which are two lines that do not intersect and are not parallel. [3:46]

This tutorial introduces trapezoids and takes a look at the special properties needed for a quadrilateral to be called a trapezoid. [5:27]

Here's a chance to see if you can combine what you know to add up resistance in series AND in parallel. Rishi is a pediatric infectious disease physician and works at Khan Academy. [3:22]

Learn about how resistance can be added up in series and in parallel (similar to electrical circuits!). Rishi is a pediatric infectious disease physician and works at Khan Academy. [10:33]

This video tutorial describes how to classify quadrilaterals using key characteristics such as parallel sides and right angles. [4:27]

Quadrilaterals are explored in this video lesson. The tutorial describes the characteristics of various quadrilaterals. Students can check their understanding with an assessment. [6:17]

This lesson 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. Students can check their understanding with an...

This detailed lesson uses slope, midpoint, and distance formulas to prove a quadrilateral is a rectangle in the coordinate plane.

Coordinate geometry of rectangles is investigated in this video lesson. The tutorial demonstrates how to use the midpoint, distance, and slope formulas to determine if a quadrilateral is a rectangle on a coordinate plane. [17:26]

This video lesson demonstrates how to interpret the slope of linear equations to determine if lines are parallel or perpendicular. Students can check their understanding with an assessment.

This lesson provides a video that shows examples of various quadrilaterals in the real world. A notes sheet follows describing the characteristics of each quadrilateral and how to find the area of several figures. [3:37]

This lesson discusses parallel construction and why it is important. [5:04] L.9-10.1a Parallelism

This tutorial shows you how to find x so two lines are parallel. [2:47]

In this simulation, the cell will be used to charge a capacitor. The capacitor will then be used to operate two light bulbs until the capacitor is discharged.

Here's a chance to see if you can combine what you know to add up resistance in series AND in parallel. Rishi is a pediatric infectious disease physician and works at Khan Academy. [3:21]

How to calculate the current through a resistor in parallel using equivalent resistance and Ohm's law. [4:32]

The slope of parallel lines is discussed in this lesson. It is 4 of 5 in the series titled "Slope of Parallel Lines."

The slope of parallel lines is discussed in this lesson. It is 1 of 5 in the series titled "Slope of Parallel Lines."

Determine whether planes will intersect or will not intersect in this video lesson.Check your understanding with a quick assessment. [3:27]

This video tutorial demonstrates how to draw three-dimensional figures such as a cube and triangular prism. [4:28]