A building casts a shadow that is 15 meters in length The distance from the top of the building to the top of the shadow is 25 m
1 answer:
Answer:
20 meters
Step-by-step explanation:
The shadow of the building will look like a right triangle. In this problem, the hypotenuse of the triangle is 25 meters, and one of the sides is 15 meters. What we are trying to find is the length of the other side.
We can do this by using pythagoreans theorem.
So, the last side (or the height of the building) is 20 meters.
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Answer:
The direction cosines are:
,
and
with respect to the x, y and z axes respectively.
The direction angles are:
40°, 81° and 52° with respect to the x, y and z axes respectively.
Step-by-step explanation:
For a given vector a = ai + aj + ak, its direction cosines are the cosines of the angles which it makes with the x, y and z axes.
If a makes angles α, β, and γ (which are the direction angles) with the x, y and z axes respectively, then its direction cosines are: cos α, cos β and cos γ in the x, y and z axes respectively.
Where;
cos α = ---------------------(i)
cos β = ---------------------(ii)
cos γ = ----------------------(iii)
<em>And from these we can get the direction angles as follows;</em>
α = cos⁻¹ ( )
β = cos⁻¹ ( )
γ = cos⁻¹ ( )
Now to the question:
Let the given vector be
a = 5i + j + 4k
a . i = (5i + j + 4k) . (i)
a . i = 5 [a.i <em>is just the x component of the vector</em>]
a . j = 1 [<em>the y component of the vector</em>]
a . k = 4 [<em>the z component of the vector</em>]
<em>Also</em>
|a|. |i| = |a|. |j| = |a|. |k| = |a| [since |i| = |j| = |k| = 1]
|a| =
|a| =
|a| =
Now substitute these values into equations (i) - (iii) to get the direction cosines. i.e
cos α =
cos β =
cos γ =
From the value, now find the direction angles as follows;
α = cos⁻¹ ( )
α = cos⁻¹ ( )
α = cos⁻¹ ( )
α = cos⁻¹ (0.7715)
α = 39.51
α = 40°
β = cos⁻¹ ( )
β = cos⁻¹ ( )
β = cos⁻¹ ( )
β = cos⁻¹ ( 0.1543 )
β = 81.12
β = 81°
γ = cos⁻¹ ( )
γ = cos⁻¹ ()
γ = cos⁻¹ ()
γ = cos⁻¹ (0.6172)
γ = 51.89
γ = 52°
<u>Conclusion:</u>
The direction cosines are:
,
and
with respect to the x, y and z axes respectively.
The direction angles are:
40°, 81° and 52° with respect to the x, y and z axes respectively.
Answer:
Option B and D are correct.
Step-by-step explanation:
Given: A line passes through the points (2,4) and (5,6).
* Case 1:
If a line passes through the points (2, 4) and (5, 6)
Point slope intercept form:
for any two points and
then the general form for linear equations where m is the slope given by:
First calculate slope for the points (2, 4) and (5, 6);
then, by point slope intercept form;
* Case 2:
If a line passes through the points (5, 6) and (2, 4)
First calculate slope for the points (5, 6) and (2, 4);
then, by point slope intercept form;
Yes, the only equation of line from the given options which describes the given line are;
and