Perimeter Explorer (Triangle)
Perimeter · Class IV
Add all three sides of a triangle.
5 u
type a value
120
7 u
type a value
120
9 u
type a value
120
Live values
- Perimeter21
- Is it possible? (triangle inequality)1
Live readout
Perimeter21
Is it possible? (triangle inequality)1
Side a5 u
Side b7 u
Side c9 u
Formulas in this lab
- Perimeter
- Is it possible? (triangle inequality)
Tip: The two shorter sides must add to more than the longest side!
Frequently asked questions
▶What is the perimeter of a triangle?
It is the total length all the way around the triangle. Just add the three sides. A triangle with sides 3, 4 and 5 has perimeter 12.
▶How do I use the triangle perimeter lab?
Use three sliders for the three sides. The lab draws the triangle and adds up the sides one by one. The final perimeter is shown clearly.
▶When do we measure triangle perimeters?
If you want to put fairy lights around a triangle-shaped chart for Republic Day or sticker tape on the edges of a samosa cut-out, you need the perimeter.
▶Triangle tip
The two shorter sides of a triangle must add up to more than the longest side, or the triangle cannot close. Try side lengths 1, 1 and 5 and you will see the triangle break.