9514 1404 393
Answer:
1/3
Explanation:
The area of the rectangle is ...
A = lw = (21)(12)
The area of the shaded triangle is ...
A = 1/2bh = 1/2(14)(12) = (7)(12)
Then the fraction of the rectangle that is shaded is ...
(shaded area)/(rectangle area) = (7)(12)/((21)(12)) = 7/21 = 1/3
1/3 of the rectangle is shaded.