1. ## geometry problem

A picture frame has one side of length 17.2cm, a side measuring 12.9cm and a diagonal length of 21.5cm.

is the frame rectangular??

4 marks

Help!! what topic do i use?

2. Originally Posted by scoobydoo
A picture frame has one side of length 17.2cm, a side measuring 12.9cm and a diagonal length of 21.5cm.

is the frame rectangular??

4 marks

Help!! what topic do i use?
Pythagoras theorem

$a^2+b^2=c^2$ where $a,b$ are sides and $c$ is diagonal.

3. Originally Posted by scoobydoo
A picture frame has one side of length 17.2cm, a side measuring 12.9cm and a diagonal length of 21.5cm.

is the frame rectangular??

4 marks

Help!! what topic do i use?
consider

$a^2+b^2=c^2$

$17.2^2+12.9^2=21.5^2$

$295.84+166.41=462.25$

$462.25=462.25$

what does that tell you?

edit: Air beat me to it!

4. thanks for the help!!