Brilliant
Courses
Practice
Algebra
Geometry
Number Theory
Calculus
Discrete Mathematics
Basic Mathematics
Logic
Classical Mechanics
Electricity and Magnetism
Computer Science
Quantitative Finance
Chemistry
Community
Sign up
Log in
Excel in math and science
Master concepts by solving fun, challenging problems.
It's hard to learn from lectures and videos
Learn more effectively through short, interactive explorations.
Used and loved by over 6 million people
Learn from a vibrant community of students and enthusiasts,
including olympiad champions, researchers, and professionals.
Log in with Facebook
Log in with Google
or
Log in with email
Join using Facebook
Join using Google
or
Join using email
New user?
Sign up
Existing user?
Log in
Arrrrgghhh My Eyes
Logic
Level 4
How many triangles are in this picture?
Submit
Excel in math and science
Master concepts by solving fun, challenging problems.
It's hard to learn from lectures and videos
Learn more effectively through short, interactive explorations.
Used and loved by over 6 million people
Learn from a vibrant community of students and enthusiasts,
including olympiad champions, researchers, and professionals.
Your answer
seems reasonable.
Find out if you're right!
Sign up to access problem solutions.
That seems reasonable.
Find out if you're right!
Log in with Facebook
Log in with Google
or
Log in with email
Join using Facebook
Join using Google
or
Join using email
New user?
Sign up
Existing user?
Log in
×
Problem Loading...
Note Loading...
Set Loading...
