Question

Find what the question is asking

Answer 1

`\phi=\theta a2`

Explanation:

see the attached figure to better understand the problem

we know that

In the figure ABCD

`m<ADC=\theta a1`

`m<DAB=90\°`

`m<ABC=90\°`

`m<DCB=90\°+\phi`

Remember that the sum of the internal angles in a quadrilateral is equal to
`360\°`

so

`\theta a1+90\°+90\°+90\°+\phi=360\°`

`\theta a1+\phi=90\°` -----> complementary angles

and

`\theta a1+\theta a2=90\°` -------> complementary angles too

so

`\phi=\theta a2`