Math - trigonometry

posted by .

A bridge is 70m long. From the ends of the bridge the angles of depression of a point on a river under the bridge are 41 degrees and 48 degrees. How high is the bridge above the river?

  • Math - trigonometry -

    The point is obviously not under the MIDDLE of the bridge because the angles are not equal. I will assume however that it is directly under the bridge.

    Let x be the distace by which the point is displaced from being below the middle of the bridge. Let h be the height of the bridge.

    h/(35 + x) = sin 41

    h/(35 - x) = sin 48

    (35-x)/(35+x) = sin 41/sin48 = 0.88281
    35 - x = 30.899 + .88281x

    Solve for x and then solve for h.

  • Math - trigonometry -

    hlkh

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Writing

    How can I end this? ____ The bridge I made a model of is the Sydney Harbor Bridge. The bridge is located at Sydney, Australia. The Sydney Harbor Bridge is the main way to cross the Sydney Harbor carrying rail, vehicular, and pedestrian
  2. trig

    The high level bridge, a railway bridge that crosses the Oldman River is over 1km long. From one point on the river, the angle of elevation of the top of the bridge is 62.6 degrees. From a point 20m closer to the bridge, the angle …
  3. math (trig)

    from the top of a bridge over the burlington canal, maria looks down at a sailboat at an angle of depression 15 degrees.the bridge is 18m above the water. calculate the horizontal distance from the bridge to the sailboat
  4. Math, Trig

    The high level bridge, a railway bridge that crosses the Oldman River is over 1km long. From one point on the river, the angle of elevation of the top of the bridge is 62.6 degrees. From a point 20m closer to the bridge, the angle …
  5. algebra

    You live near a bridge that goes over a river. The underside of the bridge is an arch that can be modeled with the function y=-0.000475x^2+0.851x, where x and y are in feet. How high above the river is the bridge(the top of the arch)?
  6. algebra

    You live near a bridge that goes over a river. The underside of the bridge is an arch that can be modeled with the function y=-0.000475x^2+0.851x, where x and y are in feet. How high above the river is the bridge(the top of the arch)?
  7. algebra

    You live under a bridge that goes over a river. the underneath side of the bridge is an arc that can be modeled with the function y=-0.000407x^2+0.658x.Where x and y are in feet. How high is the bridge?
  8. algebra

    You live under a bridge that goes over a river. the underneath side of the bridge is an arc that can be modeled with the function y=-0.000407x^2+0.658x.Where x and y are in feet. How high is the bridge?
  9. AP Physics

    A bridge 30 m long crosses a chasm. If the bridge is inclined at angle of 20 degrees to the horizontal, what is the difference in height of the two ends of the bridge?
  10. Math-soh cah toa

    A bridge is 140m long.From the ends of the bridge, the angles of depression of a point on the river under the bridge is 41° and 48°. How high is the bridge above the river to the nearest meter. ( I know the answer is 68m, I just …

More Similar Questions