c^2 = a^2 + b^2 - 2(ab)(cos C)
c^2 + 2(ab)(cos C) = a^2 + b^2
2(ab)(cos C) = a^2 + b^2 - c^2
cos C = (a^2 + b^2 - c^2) / 2ab - Answer choice E
Hope this helps! :)
Answer:
x = -5
Step-by-step explanation:
4-2(x+7)=3(x+5)
Distribute
4 -2x-14 = 3x+15
Combine like terms
-2x-10 = 3x+15
Add 2x to each side
-2x-10+2x= 3x+15+2x
-10 = 5x+15
Subtract 15 from each side
-10-15 = 5x+15
-25 = 5x
Divide by 5
-25/5 = 5x/5
-5 =x
Answer:
ED = 6
Step-by-step explanation:
Use Pythagorean theorem to find the length of BE
100-64=x^2
x=6
because triangle BEA, and triangle DEA are congruent, the measure of BE, and DE are the same because of CPCTC
BE=DE=6
Answer:
Area of rectangle is 741.12km^2
Area of square is 1474.56km^2
Step-by-step explanation:
Formula for Area of a rectangle= length x breadth
Area = l x b = 19.3 km x 38.4 km (substitute the numbers)
Area = 741 km^2
OR
Area of square = length x length
Area = l x l = 38.4 x 38.4
Area = 1474.56 km^2