Answer:
13
Step-by-step explanation:
What????????????????????????????
Answer:
first answer
Step-by-step explanation:
the first symbols mean : congruent.
the second symbols mean : parallel.
therefore answer option 1 is the direct translation of "if opposite sides of a quadrilateral are congruent, then it is a parallelogram" (= each of the 2 pairs of opposite sides consists of parallel sides).
Try this option:
According to property such triangle
1. area=0.5*a*b, where a and b - the sides of angle 90°.
Using this equation: 180=0.5*40*b, ⇒ b=9.
2. c²=a²+b², ⇒c=√(9²+40²)=41 - the third side of the triangle;
3. Perimeter=a+b+c=9+40+41=90 cm.
answer: 90 cm.
Answer:
Options (2) and (3)
Step-by-step explanation:
Let, 

-8 + 8i√3 = a² + b²i² + 2abi
-8 + 8i√3 = a² - b² + 2abi
By comparing both the sides of the equation,
a² - b² = -8 -------(1)
2ab = 8√3
ab = 4√3 ----------(2)
a = 
By substituting the value of a in equation (1),


48 - b⁴ = -8b²
b⁴ - 8b² - 48 = 0
b⁴ - 12b² + 4b² - 48 = 0
b²(b² - 12) + 4(b² - 12) = 0
(b² + 4)(b² - 12) = 0
b² + 4 = 0 ⇒ b = ±√-4
b = ± 2i
b² - 12 = 0 ⇒ b = ±2√3
Since, a = 
For b = ±2i,
a =
= 
= 
But a is real therefore, a ≠ ±2i√3.
For b = ±2√3
a = 
a = ±2
Therefore, (a + bi) = (2 + 2i√3) and (-2 - 2i√3)
Options (2) and (3) are the correct options.