Solve the triangle. km, km, Apply the rules regarding the use of significant digits after all computations are complete.

A) km
B) km
C) km
D) km
E) km

Question

Solve the triangle.  ​ km,   km,   ​ Apply the rules regarding the use of significant digits after all computations are complete.
​
A) km 
B) km 
C) km 
D) km 
E) km

Quizplus · Accepted Answer

Since we are given all three sides of the triangle, we can use the Law of Cosines to find any of the angles. Using the Law of Cosines with sides a = 11 km, b = 11 km, c = 11 km, we get:
c^2 = a^2 + b^2 - 2ab*cos(C)
11^2 = 11^2 + 11^2 - 2(11)(11)*cos(C)
cos(C) = (11^2 + 11^2 - 11^2) / (2(11)(11))
cos(C) = 1/2
C = 60 degrees
Since we know that two of the sides are equal in length, we can conclude that this is an equilateral triangle. Therefore, all angles are equal to 60 degrees and all sides are equal to 11 km. The answer is B, 11 km.

Solve the Triangle