# geometry problem

• Jan 5th 2009, 01:54 PM
scoobydoo
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?
• Jan 5th 2009, 01:57 PM
Simplicity
Quote:

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

\$\displaystyle a^2+b^2=c^2\$ where \$\displaystyle a,b\$ are sides and \$\displaystyle c\$ is diagonal.
• Jan 5th 2009, 01:59 PM
TheMasterMind
Quote:

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

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

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

\$\displaystyle 295.84+166.41=462.25\$

\$\displaystyle 462.25=462.25\$

what does that tell you?

edit: Air beat me to it!
• Jan 5th 2009, 02:01 PM
scoobydoo
thanks for the help!! :)