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
My math teacher time me is easier to do it after
The <em>correct answer</em> is:
400,000.
Explanation:
The third digit in 399 is 9. To round to this place value, we inspect the digit behind it. If the digit is 5 or greater, we round up; if it is less than 5, we round down.
The digit behind 9 is 7. Since it is greater than 5, we round up. This would ordinarily put the number up 1; however, doing that makes the 9 a 10, which in turn makes the next number 10, and the next number 4. This gives us 400,000.
Rearrange the polynomial:
a^2–2ab+b^2 - c^2
((a-b)(a-b))-c^2
(a-b)^2-c^2
Set x =a-b and y=c. The formula becomes
x^2-y^2
factoring this polynomial, we get
(x+y)(x-y)
Substituting back, we get:
(a+b+c)(a+b-c)
Let’s multiply it out to check:
A^2 -ab ac
- ab B^2 -bc
-ac bc -c^2
Answer:
Step-by-step explanation:
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