S=(a+b)×h÷2
= 10+2× 12÷2
= 12× 12÷2
= 144÷2
=72
The triangle above
S=ah÷2
=3×4÷2
=6
Lower trapezoid
=(4+6)×4÷2
=20
72-6-20=46
If you are satisfied, please adopt it. Thank you for your cooperation! ~