Question

Find the perimeter of each of the following shapes :

1. A triangle of sides 3 cm, 4 cm and 5 cm.
2. An equilateral triangle of side 9 cm.
3. An isosceles triangle with equal sides 8 cm each and third side 6 cm.

Answer 1

(a) $\text{Perimeter of}\; \triangle\; ABC$ = $AB + BC + CA$

= $3$ $cm$ + $5$ $cm$ + $4$ $cm$
= $12$ $cm$

---

(b) $\text{Perimeter of equilateral}\; \triangle \;ABC$ = $3 \times side$

= $3 \times 9$ $cm$
= $27$ $cm$

---

(c) $\text{Perimeter of}\; \triangle\; ABC$ = $AB + BC + CA$

= $8$ $cm$ + $6$ $cm$ + 8 $cm$
= $22$ $cm$