8c-3d is the correct answer
Answer:
Area of the shaded region = 1.72r²
Step-by-step explanation:
Radius of the circle = r
Length of the rectangle = 4r
Width of the rectangle = 2r
Area of the circle = πr²
Area of the rectangle = Length × Width
= 4r × 2r
= 8r²
Area of the shaded region = Area of the rectangle - 2 × Area of the circle
= 8r² - 2 × πr²
= 8r² - 2πr²
= r²(8 - 2π)
= r²(8 - 2 × 3.14)
= r²(8 - 6.28)
= 1.72r²
A cube number is an integer which is a third power of another integer.
A triangular number is a number that counts the objects that can form equilateral triangle (sorry, I cribbed it a little from Wikipedia; it's difficult to explain). Just look at the picture.
<span />
The legs are 12 cm each, so the hypotenuse is√(144+144)=12√2☺☺☺☺
B is the correct answer I think