Answer:
-8/15
Step-by-step explanation:
Answer:
What do not you understand?
Answer:
cosA = √(21/25)
Step-by-step explanation:
We know
sin²(A) + cos²(A) = 1
Next, we know that sin(A) = 2/5. Plugging that into our equation, we get
(2/5)² + cos²A = 1
4/25 + cos²A = 1
subtract 4/25 from both sides to isolate cos²A
cos²A = 1 - 4/25 = 25/25-4/25 = 21/25
square root both sides to get
cosA = √(21/25)
We do not include -√(21/25) in our possible answer for cosA because this is in quadrant 1, so cosA must be positive.
Answer:
Step-by-step explanation:
What we know
total sum of angles = 540 deg
3/2 b cam also be written as 1.5b degrees.
So 1.5b + (b+45) + (2b - 90) +90 = 540
Step 1 -- get rid of parenthesis
1.5b + b + 45 +2b -90 +90 =540
Step 2 -- combine the like expressions
4.5b + 45 = 540
Step 3 -- subtract 45 from both the sides
4.5b = 495
Step 4 -- divide 4.5 from both the sides
b = 110 ----- not the right answer
Thats not right okay im sorry
but i guess if it is not 110 it should be 100, 90 etc.
90 = b is correct
