What is the total area! pls ! formula: a=1/2bh for triangle and a=bh for rectangle! ty!

100 in^2
20, represents the full base. but the rectangle’s base is 10. both triangles are equal so 20-10 equals 10 and split them evenly on both sides.
6•5=30/2=15
since you have two equal triangles your total answer is 30. then you do 10•7 which is 70.

Think of it this way for eery even number there is an odd number that +1 it so if you find the difference between those it is 1 
(EX: 1  and 2) (EX: 1+3 and 2+4) 
so there are 500 odd numbers so when you add it up the evens add up 500 more