Set up an equation 20=k(0.4)....to find k divide 20 by 0.4
Answer:

Step-by-step explanation:
Look at the picture.
The formula of an area of a triangle:

<em>b</em><em> - base</em>
<em>h</em><em> - height</em>
<em />
We need a length of a height.
Use the Pythagorean theorem:

We have:

Substitute:

<em>subtract 25 from both sides</em>

Calculate the area:

Answer:
c
Step-by-step explanation:
1 + tan²theta = sec²theta
tan²theta = 3² - 1
tan²theta = 8
tan theta = sqrt(8)
Positive because Quadrant 1
sqrt(8) = sqrt(4×2) = sqrt(4)×sqrt(2)
= 2×sqrt(2)