Answer: 4 ft/s
Explanation:
Given
height of man
speed of person 
height if street light
Let x be the distance between person and street light and y be the length of his shadow
From diagram
as the two triangle ADE and ABC are similar therefore we can say that




differentiate above Equation w.r.t time we get


<em>The first blank is </em><em>robust watermark</em>; a robust watermark will not resist tampering.
<em>The second blank is </em><em>fragile watermark</em><em>;</em> a fragile watermark will resist manipulations of the media.
<h3>What is a watermark?</h3>
A watermark is a faint design made in paper during manufacture that is visible when held against the light and clearly identifies the maker.
The watermark can be of different types depending on the application and they include:
- A robust watermark will not resist tampering.
- A fragile watermark will resist manipulations of the media.
Thus, The first blank is robust watermark; a robust watermark will not resist tampering.
The second blank is fragile watermark; a fragile watermark will resist manipulations of the media.
Learn more about watermark here:.
brainly.com/question/24206908
#SPJ1
professional is the answer
3rd