Answer:
40 cm
Step-by-step explanation:
Since the triangles are similar then the ratio of corresponding sides are equal.
Compare the ratio of the 2 smallest sides
[tex]\frac{12}{3}[/tex] = 4 ← scale factor
Thus the longest side of the other triangle is 4 times the longest side of the first triangle , that is
longest side = 4 × 10 = 40 cm
