SOLUTION: A lecture theatre in the shape of a prism has a height of 9 metres. The floor of the lecture theatre ABCD is an isosceles trapezium. AB=45 metres, CD=17 metres, AD-21 metres, and

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Question 1185694: A lecture theatre in the shape of a prism has a height of 9 metres. The floor of the lecture theatre ABCD is an isosceles trapezium. AB=45 metres, CD=17 metres, AD-21 metres, and AB is parallel to DC. J is a point on AB such that DJ and AB are perpendicular. What is the floor area of the lecture theatre?
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The area of a trapezoid is the height times the average of the bases:
Area = (DJ)*((AB+CD)/2)

You are given AB and CD.

To find DJ, use the Pythagorean Theorem on triangle AJD. Note that, since the trapezoid is isosceles, AJ is half of (AB-CD).

You can do the calculations.