`color{#adc6b2}{ʚ}color{#41998a}{\text{V}}color{#56b7a7}{\text{u}}color{#adc6b2}{ɞ}`

`*`Xét tứ giác `ABCD`

`hat{A}+hat{B}+hat{C}+hat{D}=360^@`

`=>x=hat{C}=360^@-110^@-150^@-60^@=40^@`

``

`*` Xét tứ `EFGH`

`hat{E}+hat{F}+hat{G}+hat{H}=360^@`

`=>hat{E}+hat{F}+2hat{G}=360^@`

`=>x=hat{G}=(360^@-90^@-65^@)/2=102,5^@`

``

`*` Xét tứ giác `MNPQ`

`hat{M}+hat{N}+hat{P}+hat{Q}=360^@`

`(180^@-90^@)+hat{N}+(180^@-100^@)+(180^@-70^@)=360^@`

`90^@+hat{N}+80^@+110^@=360^@`

`=>x=hat{N}=360^@-90^@-80^@-110^@=80^@`