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    Basically I get up to figuring out that BD is 8cm but I have no idea how to get from there to finding the length of BC. I'm sure it's really obvious but I just can't figure it out! Please could someone help me out?

    So far my working is:
    OB/Sin30=8/Sin90
    OB/Sin30=8
    OB=8Sin30
    OB=4
    Then because OB=OD, BD=8cm

    Thanks for the help!

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    "The angle in a semicircle is a right angle"
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    Maybe this will be useful.
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    (Original post by BabyMaths)
    "The angle in a semicircle is a right angle"
    Of course! Dammit, I knew it was something really obvious. Thank you very much!
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    <BCD is 90 degrees so just use trigonometry
 
 
 
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