My daughter is in 3rd grade and starting some basic geometry. Her homework today shows a parallelogram with the 4 corners labeled LMNO. Her first question is give two names for this parallelogram. Her answers were LM and NO. I told her that those were two of the sides, but that the parallelogram as a whole must be labeled with all four corners, so two names could be LMNO or NOLM. She says that I'm wrong...am I? She forgot her math book at school, so I cannot check there. She was also asked to name the 2 triangles formed after she drew the diagonal LN. She wrote LN and NL. I told her that was the name of the diagonal, but that the triangles would be LNO and LMN. She again says that I am wrong. It has been awhile since I've done this stuff, but I can't be that far off. Please let me know what you think!

Question

My daughter is in 3rd grade and starting some basic geometry.  Her homework today shows a parallelogram with the 4 corners labeled LMNO.  Her first question is give two names for this parallelogram.  Her answers were LM and NO.  I told her that those were two of the sides, but that the parallelogram as a whole must be labeled with all four corners, so two names could be LMNO or NOLM. She says that I'm wrong...am I?  She forgot her math book at school, so I cannot check there.  She was also asked to name the 2 triangles formed after she drew the diagonal LN.  She wrote  LN and NL.  I told her that was the name of the diagonal, but that the triangles would be LNO and LMN.  She again says that I am wrong.  It has been awhile since I've done this stuff, but I can't be that far off.  Please let me know what you think!

Marth · Answer

LM and NO describe lines between two points. A parallelogram requires 4 points, and a triangle requires 3.