How do I know if this is a right angled triangle? (1 Viewer)

[BlueGas]

Basically I was trying to figure out the area for this triangle and I couldn't tell it was a right angled triangle after I looked at the answers, how would I know if this is a right angled triangle?

 

[nisak]

Basically I was trying to figure out the area for this triangle and I couldn't tell it was a right angled triangle after I looked at the answers, how would I know if this is a right angled triangle?

the second part of the question tells you to the find the perpendicular distance so you use that to find the area and then you find the distance from A to C to then to A=0.5bh

 

[kawaiipotato]

It wouldn't be. It's right angled if the two lines are perpedicular ie. their gradients multiplied equal -1
The second part made you find the perpendicular distance (the 'length' of the line when you draw it from B connecting to line AC at a right angle) which will then split the triangle into two (not necessarily equal) right angled triangles

 

[Flop21]

Pythagoras theorem. c^2=a^2+b^2. If the sides of the triangle (distance formula) satisfy pythagoras theorem, then it's a right angled triangle.

 

[LC14199]

Pythagoras theorem. c^2=a^2+b^2. If the sides of the triangle (distance formula) satisfy pythagoras theorem, then it's a right angled triangle.

This. Simple test

 

[Drsoccerball]

You don't need to know what triangle it is if you are given the perpendicular distance.

 

[sharoooooo]

just get the gradient for AB and then the gradient for BC.

then multiply the gradients together, and it should =-1.

hence, perpendicular (right angle)

 

[obliviousninja]

Or you could just use a protractor?

 

[Flop21]

Or you could just use a protractor?

"not to scale"