Answer:
Can't type the Full solution
I'll solve for the triangle with angles 1 and 2
You can go for the rest.
CosA = 0.28
Taking the cos-¹(0.28) to determine its Magnitude
A=73.74°
Now
We can use sine Rule to get the values of each of the other angles in the triangle
For the first triangle
Applying sine rule
What basically happens in the rule is... Each side divided by the angle opposite it.
Look below
The angle opposite 40cm is angle '2' and the angle opposite 41cm is 90°
We have this sine rule when all three sides are given with ONE ANGLE(90° is the given angle in this case)
So
Each side over the angle opposite it
We go!!
Let's call angle "2" an alphabet. Say Q
41/sin90 = 40/SinQ
SinQ = 40sin90/41
Recall sin90=1
SinQ = 40/41
Q= Sin-¹(40/41)
Q= 77.32°
so angle 2 is 77.32°
Now apply this to get others
Angle '1' should be 12.68°
Angle "3" should be 16.26°
Angle "4" should be 73.74°
Therefore
conclusion
Angle "4" is same as A. That's the angle we looking for
Option 4 IS CORRECT!!