Answer:
C. 28
Explanation:
From the diagram diagram;
and
.
- The opposite sides of a rhombus are parallel.
- The diagonals act as transversals.
- Therefore the co-interior angles will add up to 180 degrees.
The pair of co-interior angles are
and
.
Also the diagonals of a rhombus bisect corner angles.
This implies that:
.
.
The co-interior angles are supplementary so we form the equation:
![\angle BAD+\angle ABC=180\degree](https://img.qammunity.org/2020/formulas/mathematics/high-school/8xpys8ja1nw9qrcvfvj2btrwq7ekoxrp7p.png)
![\implies 2(x+6)\degree+2(2x)\degree=180\degree](https://img.qammunity.org/2020/formulas/mathematics/high-school/vex2ymc3ka2mqk05z6tw09kbtxj69w7fct.png)
Expand the parenthesis to get:
![\implies 2x+12+4x=180\degree](https://img.qammunity.org/2020/formulas/mathematics/high-school/d5mp1286ofwidjht85ii9g59v6p2bukwk2.png)
Group the similar terms:
![\implies 2x+4x=180-12](https://img.qammunity.org/2020/formulas/mathematics/high-school/lazowgokpdva4heji4gvnlxho5c6l0hrcv.png)
Simplify
![\implies 6x=168](https://img.qammunity.org/2020/formulas/mathematics/high-school/d1r9z8tyo5cgrdkz0wtfvgg8q62eefjjj4.png)
Divide both sides by 6.
![\implies (6x)/(6)=(168)/(6)](https://img.qammunity.org/2020/formulas/mathematics/high-school/zwh0r7ccgw59bvuu4mu3amn26p8ga121x8.png)
![\therefore x=28](https://img.qammunity.org/2020/formulas/mathematics/high-school/3gu67o5xsxt3k25dx85q1nng4lzokvvdl8.png)
The correct answer is C.