Answer:
![D = 52.5](https://img.qammunity.org/2021/formulas/geography/high-school/95c9optey82cjqzm3jo5qocvu6tnc82dbi.png)
Step-by-step explanation:
See attachment for diagram
Given
![A = 3x](https://img.qammunity.org/2021/formulas/geography/high-school/jfdmznfmqqrr1sud9591xq9accmpn66o9e.png)
![B = x + 10](https://img.qammunity.org/2021/formulas/geography/high-school/sqghcqc8zr9fth60xawhghktdim7zesa81.png)
Required
What is the measure of angle D? ------ Missing part of the question
From the attachment, we have that
A is adjacent to B
And adjacent angles of a parallelogram add up to 180.
i.e.
![A + B = 180](https://img.qammunity.org/2021/formulas/geography/high-school/i7obx29b25owyce6khofetjm5wdgg5x62m.png)
Substitute values for A and B
![3x + x +10 = 180](https://img.qammunity.org/2021/formulas/geography/high-school/bkvw37rnen22atroya5fu79tbj0qhj0cz4.png)
![4x +10 = 180](https://img.qammunity.org/2021/formulas/geography/high-school/rqoetteoiufcsk8o8zji4k5dwqh03cc3iv.png)
Collect Like Terms
![4x = 180 - 10](https://img.qammunity.org/2021/formulas/geography/high-school/y7lhiw04tdh0cqf0k8wtmkynr4taxz0wfw.png)
![4x = 170](https://img.qammunity.org/2021/formulas/geography/high-school/imx5ywib9e2xt9j2tavpor9lbd7uet97z0.png)
Solve for x
![x = 170/4](https://img.qammunity.org/2021/formulas/geography/high-school/7810raw0xapanw1tgb59xw1dd7ov6vhkdv.png)
![x = 42.5](https://img.qammunity.org/2021/formulas/geography/high-school/lzz3voj8l6q2pcaw514ysoruyplyhpqvoo.png)
Also from the attachment,
D is at opposite of B
And opposite angles of a parallelogram are equal
i.e.
![D = B = x + 10](https://img.qammunity.org/2021/formulas/geography/high-school/o8320ldtcs6tpw0w2c29f9i9nnfy5vztku.png)
![D = x + 10](https://img.qammunity.org/2021/formulas/geography/high-school/vbet4nkpjccoviaepjd6sp2dvplgyndya4.png)
Substitute 42.5 for x
![D = 42.5 + 10](https://img.qammunity.org/2021/formulas/geography/high-school/4n6c8l62cm3af59pfvkr3t0bs9vc45qhid.png)
![D = 52.5](https://img.qammunity.org/2021/formulas/geography/high-school/95c9optey82cjqzm3jo5qocvu6tnc82dbi.png)