I think the answer is D. the upper surface of undergound water.
Concave is not a type of mechanical wave because it doesn’t need a medium for propagation.
It is called <span>absolute humidity.
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Answer:
a. 1/3
In the picture- D. 4
Explanation:
The product of the gradients of perpendicular lines =-1
m1m2=-1
Given an equation of a line in the form y=mx+c, m is the gradient of the line.
For y= -3x-9, m=-3
m1m2=-1
-3×m2=-1
m2=1/3
The gradient of the perpendicular line is 1/3
For the question in the picture, y=-1/4x-9, m=-1/4
m1×m2=-1
-1/4m2=-1
m2=4
The slope of the line perpendicular to y=-1/4x-9 is 4
