Angles Angels left-fielder Brian Goodwin cuts parallel lines formed by the the carefully mowed field as he waits for the Oakland A's to actually hit the ball. The parallel lines are indicated by and the congruent angles are indicated with variations of .
The lines created by the crosswalk and the light pole are perpindicular, because they intersect at a 90° angle. The four right angles created by this are indicated as . This photo was taken in the Embarcadero neighborhood of San Francisco. It's not my best night photo in San Francisco, but it demonstrates geometry.
The Skydeck building (the big brown one Downtown) forms a trapezoid when photographed from the base. A trapezoid has one pair of parallel lines, which are marked in my image with a icon. Did you know that in the United Kingdom, a trapezoid is a quadrilateral (four-sided shape) with no parallel sides?
The same image of the Embarcadero from before demonstrates corresponding angles as well. Corresponding angles are found when a transversal intersects two or more parallel lines. Corresponding angles are congruent angles on the same side of a transversal. The light post intersects the light trail and the crosswalk to form four pairs of corresponding angles, one of which is shown with markers.
Vertical angles are pairs of angles formed by two angles opposite eachother at the intersection of two lines. The two platforms at the North Berkeley BART station demonstrate this. The two pairs of congruent angles are marked with and similar symbols.
Alternate exterior angles are two congruent angles that are on opposite sides of a transversal and on the outer sides of the parallel lines intersected by that transversal. The photo from the Embarcadero shows this as well. The congruent 90° angles are shown as .
An angle bisector intersects an angle, leaving two congruent angles. Two lights intersect on top of my friend Alice's head, where they are bisected by a third line. Three (or four) vertical angle pairs are formed. The angles are marked with variations of . This photo was taken at the Exploratiorium at Pier 15.
A parallelogram is a quadraliteral where opposing angles are parallel. That means that there will be two sets of parallel lines. The parallel lines are marked with variations of this symbol on my image: . This parallelogram was formed by the cables supporting the Brooklyn Bridge. You can see the skyscrapers of Manhattan in the background.
The roof of the Queen Elizabeth II Great Court at the British Museum in London, England is made up of hundreds of congtuent triangles. The two triangles I chose are congruent by SSS (side-side-side). The congruent sides are marked with variations of . Because both triangles are congruent, all parts of the triangles are congruent with their corresponding parts in other congruent triangles. For example, the angles in the top triangle are the same as the corresponding angles in the bottom triangle.
Finally, the street sign on the wall of a building in London's Chinatown is a rectangle because it has four 90° angles. That's really the only requirement for a rectangle. As a result of the four 90° angles, the opposite sides are parallel and congruent. This street sign is part of a collection of street signs I photographedd in London. It was mounted on the short wall you can see on the map.