An observer

An observer standing west of the tower sees its top at an altitude angle of 45 degrees. After moving 50 meters to the south, he sees its top at an altitude angle of 30 degrees. How tall is the tower?

Correct result:

y =  35.355 m

Solution:

A=45  B=30  x3=50 m  tanA=y:x1 tanB=y:x2  x22=x32+x12  y=x1 tanA=x2 tanB=35.355 m  x1 tanA=x2 tanB x12 tan2 A=x22 tan2 B  x12 tan2 A=(x32+x12) tan2 B  t1=(tanA)2=(tan45 )2=12=1 t2=(tanB)2=(tan30 )2=0.577352=0.33333  x12 t1=x32 t2+x12 t2 x12 (t1t2)=x32 t2  x1=x3 t2t1t2=50 0.333310.333325 2 m35.3553 m  y=x1 t1=35.3553 125 235.3553   Correctness test:  x2=y/t2=35.3553/0.333325 6 m61.2372 m  x22=x32+x12=502+35.3553225 6 m61.2372 mA=45 \ ^\circ \ \\ B=30 \ ^\circ \ \\ x_{3}=50 \ \text{m} \ \\ \ \\ \tan A=y : x_{1} \ \\ \tan B=y : x_{2} \ \\ \ \\ x_{2}^2=x_{3}^2+x_{1}^2 \ \\ \ \\ y=x_{1} \cdot \ \tan A=x_{2} \cdot \ \tan B=35.355 \ \text{m} \ \\ \ \\ x_{1} \cdot \ \tan A=x_{2} \cdot \ \tan B \ \\ x_{1}^2 \cdot \ \tan^2 \ A=x_{2}^2 \cdot \ \tan^2 \ B \ \\ \ \\ x_{1}^2 \cdot \ \tan^2 \ A=(x_{3}^2+x_{1}^2) \cdot \ \tan^2 \ B \ \\ \ \\ t_{1}=(\tan A ^\circ )^2=(\tan 45^\circ \ )^2=1^2=1 \ \\ t_{2}=(\tan B ^\circ )^2=(\tan 30^\circ \ )^2=0.57735^2=0.33333 \ \\ \ \\ x_{1}^2 \cdot \ t_{1}=x_{3}^2 \cdot \ t_{2} +x_{1}^2 \cdot \ t_{2} \ \\ x_{1}^2 \cdot \ (t_{1}-t_{2})=x_{3}^2 \cdot \ t_{2} \ \\ \ \\ x_{1}=x_{3} \cdot \ \sqrt{ \dfrac{ t_{2} }{ t_{1}-t_{2} } }=50 \cdot \ \sqrt{ \dfrac{ 0.3333 }{ 1-0.3333 } } \doteq 25 \ \sqrt{ 2 } \ \text{m} \doteq 35.3553 \ \text{m} \ \\ \ \\ y=x_{1} \cdot \ \sqrt{ t_{1} }=35.3553 \cdot \ \sqrt{ 1 } \doteq 25 \ \sqrt{ 2 } \doteq 35.3553 \ \\ \ \\ \text{ Correctness test: } \ \\ x_{2}=y / \sqrt{ t_{2} }=35.3553 / \sqrt{ 0.3333 } \doteq 25 \ \sqrt{ 6 } \ \text{m} \doteq 61.2372 \ \text{m} \ \\ \ \\ x_{22}=\sqrt{ x_{3}^2+x_{1}^2 }=\sqrt{ 50^2+35.3553^2 } \doteq 25 \ \sqrt{ 6 } \ \text{m} \doteq 61.2372 \ \text{m}



Our examples were largely sent or created by pupils and students themselves. Therefore, we would be pleased if you could send us any errors you found, spelling mistakes, or rephasing the example. Thank you!


Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:
1st comment
Be the first to comment!
avatar




Tips to related online calculators
Pythagorean theorem is the base for the right triangle calculator.
See also our trigonometric triangle calculator.

 
We encourage you to watch this tutorial video on this math problem: video1   video2

Next similar math problems:

  • Find the 10
    lines Find the value of t if 2tx+5y-6=0 and 5x-4y+8=0 are perpendicular, parallel, what angle does each of the lines make with the x-axis, find the angle between the lines?
  • Three points 2
    vectors_sum0 The three points A(3, 8), B(6, 2) and C(10, 2). The point D is such that the line DA is perpendicular to AB and DC is parallel to AB. Calculate the coordinates of D.
  • Decide 2
    vectors2 Decide whether points A[-2, -5], B[4, 3] and C[16, -1] lie on the same line
  • Angle of the body diagonals
    body_diagonals_angle Using vector dot product calculate the angle of the body diagonals of the cube.
  • Two people
    crossing Two straight lines cross at right angles. Two people start simultaneously at the point of intersection. John walking at the rate of 4 kph in one road, Jenelyn walking at the rate of 8 kph on the other road. How long will it take for them to be 20√5 km apa
  • Right angled triangle 2
    vertex_triangle_right LMN is a right angled triangle with vertices at L(1,3), M(3,5) and N(6,n). Given angle LMN is 90° find n
  • Cuboids
    3dvectors Two separate cuboids with different orientation in space. Determine the angle between them, knowing the direction cosine matrix for each separate cuboid. u1=(0.62955056, 0.094432584, 0.77119944) u2=(0.14484653, 0.9208101, 0.36211633)
  • Coordinates
    geodet Determine the coordinates of the vertices and the content of the parallelogram, the two sides of which lie on the lines 8x + 3y + 1 = 0, 2x + y-1 = 0 and the diagonal on the line 3x + 2y + 3 = 0
  • Vector perpendicular
    3dperpendicular Find the vector a = (2, y, z) so that a⊥ b and a ⊥ c where b = (-1, 4, 2) and c = (3, -3, -1)
  • Vector equation
    collinear2 Let’s v = (1, 2, 1), u = (0, -1, 3) and w = (1, 0, 7) . Solve the vector equation c1 v + c2 u + c3 w = 0 for variables c1 c2, c3 and decide weather v, u and w are linear dependent or independent
  • Coordinates of a centroind
    triangle_234 Let’s A = [3, 2, 0], B = [1, -2, 4] and C = [1, 1, 1] be 3 points in space. Calculate the coordinates of the centroid of △ABC (the intersection of the medians).
  • Parametric form
    vzdalenost Calculate the distance of point A [2,1] from the line p: X = -1 + 3 t Y = 5-4 t Line p has a parametric form of the line equation. ..
  • Set of coordinates
    axes2 Consider the following ordered pairs that represent a relation. {(–4, –7), (0, 6), (5, –3), (5, 2)} What can be concluded of the domain and range for this relation?
  • Coordinates of square vertices
    ctverec_2 The ABCD square has the center S [−3, −2] and the vertex A [1, −3]. Find the coordinates of the other vertices of the square.
  • Find the 5
    distance-between-point-line Find the equation with center at (1,20) which touches the line 8x+5y-19=0
  • Right triangle from axes
    axes2 A line segment has its ends on the coordinate axes and forms with them a triangle of area equal to 36 square units. The segment passes through the point ( 5,2). What is the slope of the line segment?
  • Points collinear
    collinear Show that the point A(-1,3), B(3,2), C(11,0) are col-linear.