Google it.... <em> </em>I just did and there is a video.
Since it's an equilateral triangle, all of the angles are the same. Since its perimeter we just need to add. So 3.5+3.5+3.5= 10.5
So the answer is 10.5
To do this, you can just multiply across. 3 times 1 equals 3 so your numerator is 3. 2 times 4 equals 8. Then, your answer would be 3/8. Hope this helps :)
The square will have area
.. (9 cm)^2 = 81 cm^2.
The two triangles together will have area
.. (9 cm)*(12 cm) = 108 cm^2.
The sum of the areas of those three shapes is
.. 81 cm^2 +108 cm^2 = 189 cm^2
