Which angles are obtuse angles in the figure shown

35.1 units

Step-by-step explanation:

Imagine a right-angled triangle with RS as hypotenuse. The base would be 3 units and the height would be 6 units. By Pythagorus:

RS²=3²+6²

RS=≈6.7 units

Imagine a right-angled triangle with RT as hypotenuse. The base would be 9 units and the height would be 12 units. By Pythagorus:

RT²=9²+12²

RT= = 15 units

Imagine a right-angled triangle with TS as hypotenuse. The base would be 12 units and the height would be 6 units. By Pythagorus:

TS²=12²+6²

TS=≈13.4 units

Perimeter=RS+RT+TS

=6.7+15+13.4

=35.1 units