Mr. J Gallagher
Introduction to Trigonometry
Uses in Real Life:
Pythagoras
Building
Trigonometry allows builders to correctly layout a right-angled wall.
Leaning Tower of Pisa
Building a house
Rugby - Ronan O Gara Kick at Goal
Sine / Cosine Rules
Bridges
Much of architecture and engineering relies on triangular supports. When you drive
across a suspension bridge, you are benefiting from trigonometry, which an engineer
used to calculate the correct length of support cables, the height of support towers,
and the angle between the two.
Chesapeake bay bridge tunnel
Building
Trigonometry also allows builders to correctly layout a curved wall, determine the
proper slope of a roof or the proper height and rise of a stairway.
Industry
Trigonometry plays a major role in industry, where it allows manufacturers to create
everything from cars to fashion. Engineers rely on trigonometric relationships to
determine the sizes and angles of mechanical parts used in machinery, tools and
equipment. This math’s plays a major role in car engineering, allowing car companies
to size each part correctly and ensure they work safely together. Even determining
length of fabric needed to craft a certain shape of skirt or shirt can be accomplished
using basic trigonometric relationships.
Sine / Cosine functions
Music
Trigonometry plays a major role in musical theory and production. Sound waves
travel in a repeating wave pattern, which can be represented graphically by sine and
cosine functions. A single note can be modeled on a sine curve, and a chord can be
modeled with multiple sine curves used in conjunction with one another. A graphical
Mr. J Gallagher
representation of music allows computers to create and understand sounds. It also
allows sound engineers to visualize sound waves so that they can adjust volume,
pitch and other elements to create the desired sound. Trigonometry plays an
important role in speaker placement as well, since the angles of sound waves hitting
our ears can influence the quality of the sound.
Electricity & Phone Lines
Modern power companies use alternating current to send electricity over longdistance wires. In an alternating current, the electrical charge regularly reverses
direction to deliver power safely and reliably to homes and businesses. Electrical
engineers use trigonometry to model this flow and change of direction, with the sine
function used to model voltage. Every time you flip on a light switch or turn on the
television, you’re benefiting from the application of trigonometry.
Mr. J Gallagher
Teaching Strategies:
Introduction to topic
Show pictures & videos before begin each area
Key information
Pictures of buildings
Use Pythagoras / Trigonometric ratio’s to find missing Side / Angle.
Maps of Places & Pictures of bridges
Pictures of Donegal, Ireland & the World. Find missing angles / sides using sine &
cosine rule.
Geogebra files
Quiz