HELPP ITS ABOUT A PYRAMID Explanation needed pleasee

Answer:
A. a triangle with an area of 20 square units
Step-by-step explanation:
note when you cut from top tip to the bottom you will get a triangle with base = 4 and height =10
Area of triangle = 1/2 * base * heighte
Area of triangle = 0.5*10*4
Area of trianle = 20 square units