Construct a triangle having sidelengths: \(5 \ cm\), \(5 \ cm\), \(7 \ cm\).
 
Construction:
 
YCIND_260823_8443_three lines_math2_16.png
 
Step 1:
 
Step 2:
 
Step 3:
 
Step 4:
 
Thus, \(PQR\) is the required triangle.
Answer variants:
Join \(PQ\) and \(PR\).
With \(Q\) as centre and \(5 \ cm\) as radius, draw an arc.
Draw a base line segment \(QR = 7 \ cm\).
With \(R\) as centre and \(5 \ cm\) as radius, draw an arc which cuts the previous arc at \(P\).