On a bicycle trail, the city is painting arrows like the one shown below:

calculate the area of the arrow by decomposing it into rectangles and triangles.
148.5 square centimeters
151.5 square centimeters
171 square centimeters
195 square centimeters

So if you imagine splitting the arrow into a triangle on top and a rectangle on the bottom, we can figure out the areas:
triangle:
The area of a triangle is (base × height)/2 so in this case 13 is the base and 3 (15 - 12) is the height, so 13 × 3 = 39, 39 ÷ 2 = 19.5 square centimeters.
rectangle:
For this, you just do base × height which would be 12 × 11 = 132.
Now you add the two values to get 151.5 as the answer. I hope this helps!