Step-by-step explanation:
Option A and B are the correct answer because it equal to 688.5 and 688.05
If you find the difference between 3 and 1 you would get 2 and then if you found the difference of 7 and 3 you would get 4. So basically the difference of the numbers is doubling. Hope this helps!
Get value of 'A' from a sin table and C is already given 90, hence B can be calculated using angle sum property of a triangle.
<span>alternately, using pythagorus th., find the third side of triangle and then you will know sinB. </span>
<span>again from sin table, get B
</span>sinA = 243/312 = 0.7788
<span>A = 51.16 degrees </span>
<span>B = 180 - 90 - 51.16 = 38.64 degrees (fourth choice) </span>