We can use a pair of compasses and a ruler to construct a triangle when the lengths of its sides are given.

* Example*

Construct a triangle *PQR* with *PQ *= 5cm, *PR* = 6 cm and *QR* = 4.5 cm.

* Solution: *

** Step 1** : Using the steps in the previous section, draw a line segment *PQ* with lengths 5 cm and mark the points *P* and *Q*.

** Step 2** : To draw *PR,* first stretch the 2 arms of the compasses 6 cm apart, place the sharp point at point *P* and mark an arc with the pencil end.

**Step 3** : To draw *QR,* adjust the compasses to 4.5 cm, place the sharp point at point *Q* and mark an arc with the pencil end. You need to draw the arc so that it will intersect with the arc drawn in step 2. Label the point of intersection as point *R*.

**Step 4** : Draw straight lines from *P* to *R* and from *Q* to *R*

The following video shows how to construct an SSS Triangle using a ruler and compass,

You can use the Mathway widget below to practice Algebra or other math topics. Try the given examples, or type in your own problem. Then click "Answer" to check your answer.