B. 25 Km. The measure of BC is 25 km.
The easiest way to solve this problem is using the cosine theorem c = √a²+b²-2ab*cos A.
BC = √AC²+AB²-2(AC)(AB)*cos A
BC = √(21km)²+(14km)²-2(21km)(14km)*cos 89°
BC = √441km²+196km²-588km²*(0.017)
BC =√637km²-10.26km²
BC = √636.74km²
BC = 25.03km ≅ 25
Answer:

Step-by-step explanation:
we have

Multiply by
both sides


Adds
both sides


First we need the distances of the sides of the polygon, because perimeter = sum of all sides.






Now, we add all sides for the perimeter:
p = d1 + d2 + d3 + d4 + d5
p = 3+5+5+3+4 = 20 units
Answer:
D. ABE =CBD by SSS.
Step-by-step explanation:
Given that AB = BD and BE = BC, the lengths of AE and CD are equal to each other. Hence, triangles ABE and BCD are congruent by SSS Theorem. The answer is D.
It would be a x/n = n √a^x
Hope this helps