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Gcse maths question HELP!!!

simmy123

I dont understand how to work it out help please :dontknow:

I need to know this week its important and thanks in advance if you work it out :biggrin:

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(edited 11 years ago)

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Reply 1

lilixxx1000

for part a: make a right angled triangle with A, B and the midpoint of BC

you know the height is 6cm and the bottom length is 4 cm (it's half of the base which is 8).

so then you're trying to find out the angle at b. so you use soh cah toa. in this case you have the opposite side and the adjacent side so you use tan.

you do the inverse tan of 6/8 which gives you 36.87 degrees to 2 decimal points.

Reply 2

simmy123

Thank you so much :getmecoat:

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Reply 3

lilixxx1000

for part b:

make a right angled triangle with A, D and the midpoint of DE. you know the bottom side is 4 cm (as it's half of 8) and the height is 7+6=13cm.

again, use soh cah toa. as you again have the opposite side and the adjacent side, use tan. do the inverse tan of 13/4 which gives 72.9 degrees.

so angle ADE = 72.9 degrees

Reply 4

sierra-bravo

For part B (and A, you must give a name of midpoints). The midpoint of [BC] is F, and the midpoint of [DE] is G.
You've BF = DG.
You've AF. So you can use soh cah toa.

For part C, you can use Pythagore.

Reply 5

lilixxx1000

for part c: use pythagorus's theorom - a2 + b2 = c2

make a right angled triangle again out of A, D and the midpoint of DE. the base is 4cm, and the height is 13 as seen above.

therefore, AD^2 = 4^2 + 13^2
so AD = 13.6