© examsiri.com
Question : 49 of 50
Marks:
+1,
-0
Solution:
In triangle
â–³ABC, given
a=26,b=30, and
cos‌C=‌, we need to find the length of side
c.
We know the cosine rule for any triangle is given by:
cos‌C=‌Substituting the known values:
‌=‌This implied expression becomes:
‌=‌Now, solve this step-by-step:
Calculate
262 and
302 :
262=676,‌‌302=900Substitute these into the equation:
‌=‌Simplify the numerator:
676+900=1576Substitute back:
‌=‌Cross-multiply to solve for
c2 :
65(1576−c2)=63×1560Compute
63×1560 :
63×1560=98280Now, solve for
c2 :
65×(1576−c2)=98280Simplify the expressions:
102440−65c2=98280Rearrange to find
c2 :
102440−98280=65c2Solve:
4160=65c2Divide by 65 to isolate
c2 :
c2=‌=64Take the square root:
c=√64=8Thus, the value of
c is 8 .
© examsiri.com
Go to Question: