Triangle Taxonomy Activity
High School Geometry • Guided Learning Visual Triangle Detective
TRIANGLE DETECTIVE LAB
Classify Any Triangle Using 2 Easy Steps: Sides & Angles
Name:
Date:
Period:
1
Step 1: Check the Sides
Count the matching tick marks | on the edges:
Scalene 0 matching sides (All different lengths)
0 Equal
Isosceles 2 matching sides (Twin sides have tick marks)
2 Equal
Equilateral 3 matching sides (All three sides have tick marks)
3 Equal
2
Step 2: Check the Corners
Look at the size of the corner angles:
Right Triangle Has exactly 1 square corner box (90°)
1 Square
Obtuse Triangle Has 1 wide open corner (Bigger than 90°)
1 Wide
Acute Triangle All 3 corners are sharp points (All under 90°)
3 Sharp
Warm-Up: Draw the Geometric Clue Symbols
Follow the simple prompt for each triangle
1. Draw a small square box □ in the right angle corner:
Makes it a Right Triangle!
2. Draw 2 tick marks | to show twin equal sides:
Makes it an Isosceles Triangle!
3. Draw 3 tick marks | on all three equal edges:
Makes it an Equilateral Triangle!
Guided Practice: Circle the Clues & Name the Triangle
Look at the picture • Circle one from each row
Triangle A 6 8 10
1. Count equal sides (0, 2, or 3):
Scalene Isosceles Equilateral
2. Check corner types:
Right (Square) Acute Obtuse
Full Name: It is a Right Scalene triangle.
Triangle B 60°
1. Count equal sides (0, 2, or 3):
Scalene Isosceles Equilateral
2. Check corner types:
Acute (Sharp) Right Obtuse
Full Name: It is an Equilateral triangle.
Triangle C 120°
1. Count equal sides (0, 2, or 3):
Scalene Isosceles Equilateral
2. Check corner types:
Acute Right Obtuse (Wide)
Full Name: It is an Obtuse Isosceles triangle.
Triangle D 50° 60° 70°
1. Count equal sides (0, 2, or 3):
Scalene Isosceles Equilateral
2. Check corner types:
Acute (Sharp) Right Obtuse
Full Name: It is an Acute Scalene triangle.
Page 1 of 2 • Visual Clue Cards & Guided Practice Turn to Page 2 for the Coloring Activity →
Part 4: Color-By-Classification Challenge 8 Separated Challenge Cards
THE GEOMETRIC COLOR CHALLENGE
1. Inspect each separated triangle • 2. Circle choices in the checklist • 3. Color each triangle!
8 Individual Cards
Master Color Key (Find Your Triangle's Type \(\rightarrow\) Color Its White Card) Use colored pencils or crayons to shade
RIGHT
Square Corner □
Color: BLUE
EQUILATERAL
All 3 Sides Equal
Color: GREEN
ACUTE ISOSCELES
3 Sharp + 2 Equal
Color: YELLOW
OBTUSE ISOSCELES
1 Wide + 2 Equal
Color: PURPLE
OBTUSE SCALENE
1 Wide + 0 Equal
Color: ORANGE
ACUTE SCALENE
3 Sharp + 0 Equal
Color: PINK
1 Clue: Square Corner
6 8 10
Color this shape: ?
2 Clue: 2 Equal Sides
40° 70° 70°
Color this shape: ?
3 Clue: 3 Equal Sides
60°
Color this shape: ?
4 Clue: Square + Twin Legs
45°
Color this shape: ?
5 Clue: 1 Wide Corner
120° 4 7 10
Color this shape: ?
6 Clue: 3 Sharp + 0 Equal
50° 60° 70°
Color this shape: ?
7 Clue: 1 Wide + 2 Equal
110°
Color this shape: ?
8 Clue: Square Corner
12 5 13
Color this shape: ?
Detective Recording Log: Circle the Clues for Triangles 1 to 8
Circle one Side type • Circle one Angle type • Color it!
1
Scalene Isosceles
Right □ Acute
BLUE
2
Scalene Isosceles
Acute Obtuse
YELLOW
3
Equilateral (3=) Scalene
Acute (60°) Right
GREEN
4
Isosceles (2=) Scalene
Right □ Obtuse
BLUE
5
Scalene (0=) Isosceles
Obtuse (Wide) Right
ORANGE
6
Scalene (0=) Isosceles
Acute (Sharp) Right
PINK
7
Isosceles (2=) Scalene
Obtuse (Wide) Acute
PURPLE
8
Scalene (0=) Isosceles
Right □ Acute
BLUE
Page 2 of 2 • Separated Triangle Cards & Color Challenge Great Job Detective! You Classified All 8 Triangles!
