# gsce math question!!!!!!!???

its a question about a teapizuim

AB is parallel to DC <ADC is thirtysix <AEC is ninety

AB is eightcm DE is fourcm and EC is tencm calculate to two decimal points the length of AE

now since neither the area of the trapezuim is given nor the area of the triangle

how do i find the height????plz explain

### 4 Answers

- 8 years agoBest Answer
Hi Esha! I'm assuming that you're an o level candidate and you're from BANGLADESH.

since you mentioned that <AEC is 90° then line AE must be line on the plane DC and E is the

point where AE meets line DC or the point at which the right angle has formed.You must understand the fact that AE is a line inside the trapezium bcoz if it were outside then the < AEC would not be 90°.

Now inside the trapezium you get a triangle ADE.<ADE is 36°,DE is 4 cm and AE is to be found.

since ADE is a right angled triangle(because angle AEC is equal to angle AED or they are angles on a straight line so sum of both angles should be 180°)

now use

tan30°=AE/DE

tan30°=AE/4 cm

AE=4 Cm*tan 30°

use calculator to calculate exact value.I strongly suggest you to draw a diagram before you do the sum so that things get more clearer to you.I wish I could draw a digram but since I can't I have write a lot to explain you things.

hope i helped :)

Plz choose my ans. as the best if i am correct.

- Anonymous8 years ago
Consider the right-angled triangle ADE.

The angle adjacent to 36° is 4 cm and you want to find the opposite, AE.

tan36° = opp/adj

tan36° = AE/4

AE = 4tan36°

AE = 2.91 cm to 2 d.p.

- heningtonLv 43 years ago
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