Answer:
A= 33 degrees
A=33°
Step-by-step explanation:
THIS IS THE COMPLETE QUESTION BELOW, ALSO CHECK THE ATTACHMENT FOR THE DIAGRAM
Law of cosines: a2 = b2 + c2 – 2bccos(A) What is the measure of S to the nearest whole degree? 19° 26° 30° 33°
EXPLANATION
Accordingto the law of cosines in
trigonometry, which gives the relationship between the lengths of the sides of a triangle to the cosine of one of its angles.
From the diagram at the attachment, the sides of the triangle are:a=10 ,b=17 ,c=18
The law can is described using the formula below;
a² = b²+ c² – 2*b*c*cos(A)
To get the angle cos(A), we make cos(A) subject of formula
cos(A)=[b²+c²-a²]/[2*b*c]
Then inserting the figures
cos (A)=[17²+18²-10²]/[2*17*18]
cos (A)=0.8382
Then find the inverse of cos(A)
A=arc cos (0.8382)
A=33.05°
A=33°( approximately)
