The areas of two similar triangles are 324 cm² and 225 cm². If the altitude of the smaller triangle is 10 cm, then the altitude of the bigger triangle in centimetres, is:

12

We have,

If ΔABC ∼ ΔPQR, then

Area of ΔABC/Area of ΔPQR = (AB/PQ)² = (BC/QR)² = (AC/PR)²

Areas of two similar triangles are 324 cm² and 225 cm².

If the altitude of the smaller triangle = 10 cm.

Let altitude of bigger triangle is a cm, then

(a/10)² = (324/225)

= a/10 = √324/225

= a/10 = 18/15

= a = (18/15) × 10

= a = 12