Find angle a2 which is 40 degrees because it is parallel to angle c.
Find the total of d1 and d2.
total of d1 and d2: 180 - 40 - 40 = 100 degrees
Find d1 and d2 separately.
100 divided by 2 = 50 degrees
Use d1 to find b1 to find total of a1 and a2.
b1 is parallel to d1 so b1 = 50 degrees
a1 and a2 = 180 - 50 - 50 = 80 degrees
a1 = 80 divided by 2 = 40
Since a1 and c1 are parallel due to alternate angles, c1 is 40 degrees
Find b2 now which requires you to do total - minus all angles in the triangle with angle b2.
180 - 40 - 50 - 40 = 50 degrees (angle b2)
AOB has b1 and a1.
40 + 50 = 90 degrees (a1 + b1 = AOB)
The answer is 90 degrees
What the guy here is gonna say
You will read for 45 minutes if your brother reads for 15 minutes.
<em><u>Explanation</u></em>
You decide to read 30 minutes longer than your brother reads.
If your brother reads 
number of minutes, then 30 minutes longer than minutes means 
minutes.
As the number of minutes you read is 
, so the equation will be: 
When your brother reads for 15 minutes, then we will just <u>plug 
into the above equation</u>. So.....
So, you will read for 45 minutes if your brother reads for 15 minutes.
