Congruent triangles (1 Viewer)

[Joshmosh2]

Hey, is there any technique that I can use for complete accuracy in determining whether triangles are congruent or not? As i went through the answers I got one wrong. I am determining them by sight and am trying to rotate them in some way. There must be a better way!

 

[Shadowdude]

You haven't learned the SSS, SAS, AAS, RHS or whatever tests yet I presume?

 

[Joshmosh2]

You haven't learned the SSS, SAS, AAS, RHS or whatever tests yet I presume?

Yes, I have learnt them. The exercise I am doing right now is to state if they are congruent or not, not prove congruency. You are basically given all the information. The problem is, some of them seem that their 'supposed' corresponding sides and angles are equal.

The one I had wrong had two sides and one angle the same on both diagrams, however was not congruent. Is there any solid method of determining if they are congruent when you are given the information? If all the values look the same, it seems that only through mental rotation could one determine whether or not the sides and angles are corresponding.

 

[Joshmosh2]

In my exercise, two corresponding sides and one corresponding angle is the same, however, one appears to be slightly taller than the other. So is sight the only way to determine questions like these? if so, there might be one or two questions that i can get wrong without realising.

 

[turntaker]

In my exercise, two corresponding sides and one corresponding angle is the same, however, one appears to be slightly taller than the other. So is sight the only way to determine questions like these? if so, there might be one or two questions that i can get wrong without realising.

Which textbook do you use?

 

[Shadowdude]

In my exercise, two corresponding sides and one corresponding angle is the same, however, one appears to be slightly taller than the other. So is sight the only way to determine questions like these? if so, there might be one or two questions that i can get wrong without realising.

Diagrams are usually not drawn to scale, you know...


If the corresponding angle is the included angle between the two sides, it's congruent.

 

[Joshmosh2]

Ahh yes! included angle is the bit that got me. The diagrams had all the corresponding sides, and the corresponding angles are equal, however they were not included angles, therefore can't prove congruency. THAT'S OP!

 

[Joshmosh2]

Which textbook do you use?

J and C for the exercise. I also use MIF and cambridge