Answer:
see explanation
Step-by-step explanation:
The sum of the 3 angles in a triangle = 180°, thus
∠1 = 180° - (72 + 57)° = 180° - 129° = 51°
The right angle at the left vertex is composed of 72° and ∠2, thus
∠2 = 90° - 72° = 18°
57° and ∠3 form a straight angle and are supplementary, thus
∠3 = 180° - 57° = 123°
∠4 = 180° - (∠2 + ∠3 ) ← sum of angles in a triangle
∠4 = 180° - (18 + 123)° = 180° - 141° = 39°
Yes it is true:
(1 - cos^2 x) = sin^2 x Sqr.(1 - cos^2 x) = sin x and (-sinx) True, since sin x negative. Also, x terminates in quadrant 3 and 4. Hope this is helpful
Answer:
64 cm²
Step-by-step explanation:
Area of a square: s²
s = 8 cm
(8)² = 64 cm²
