I'm pretty sure DEF is a scalene triangle since it looks like none of the sides are equal to each other.
Hope this helps!
May
Answer:
Option A, 80π
Step-by-step explanation:
4²×5π
= 80π
This isn't an identity, so I assume you have to solve the equation.
(1 - sin(2<em>A</em>)) (1 + cot(2<em>A</em>)) = cot(2<em>A</em>)
1 - sin(2<em>A</em>) + cot(2<em>A</em>) - sin(2<em>A</em>) cot(2<em>A</em>) = cot(2<em>A</em>)
1 - sin(2<em>A</em>) - cos(2<em>A</em>) = 0
sin(2<em>A</em>) + cos(2<em>A</em>) = 1
Multiply both sides by 1/√2, which we want to do because cos(<em>π</em>/4) = sin(<em>π</em>/4) = 1/√2. This gives
cos(<em>π</em>/4) sin(2<em>A</em>) + sin(<em>π</em>/4) cos(2<em>A</em>) = 1/√2
Then condense the left side as
sin(2<em>A</em> + <em>π</em>/4) = 1/√2
2<em>A</em> + <em>π</em>/4 = sin⁻¹(1/√2) + 2<em>nπ</em> <u>or</u> 2<em>A</em> + <em>π</em>/4 = <em>π</em> - sin⁻¹(1/√2) + 2<em>nπ</em>
(where <em>n</em> is any integer)
2<em>A</em> + <em>π</em>/4 = <em>π</em>/4 + 2<em>nπ</em> <u>or</u> 2<em>A</em> + <em>π</em>/4 = 3<em>π</em>/4 + 2<em>nπ</em>
2<em>A</em> = 2<em>nπ</em> <u>or</u> 2<em>A</em> = <em>π</em>/2 + 2<em>nπ</em>
<em>A</em> = <em>nπ</em> <u>or</u> <em>A</em> = <em>π</em>/4 + <em>nπ</em>
Answer: 67.5 meters
Step by step explanation
I think you meant the scale drawing is 9 cm so all you have to do is multiple 9 times 7.5 because 1 cm is 7.5 so if you multiple 9 times 7.5 you get how much it is in real life which is 67.5
