Please help! Will give brainlist if correct. If possible pls explain how you got the answer

Answer:
30 I think
Step-by-step explanation:
Area of a triangle is (base×height) ÷2
So that means that to solve this you'd need to do 20 (the base) ×3 (the height). This gives you 60; then you divide it by 2. This gives you 30.