Homework $1\mathrm{.}4$

$1\mathrm{.}4.$ A plane frame is restrained at joints A and $D,$ as shown in the figure. Members $AB$ and $BCD$ are pin connected at $B.$ The triangularly distributed lateral load with peak intensity of $80\frac{N}{m}$ acts on CD$.$ An inclined concentrated force of $200$ N acts at the midspan of BC $.$

$($a$)$ Find reactions at supports A and D$.$

$($b$)$ Find resultant forces in the pins at B and C $.$