Mathematics · May / June 2020 · Paper 21 · Question 13
0580
As printed in the paper
The question as text
21 cm 13.5 cm 18 cm C D E B A NOT TO SCALE C lies on a circle with diameter AD. B lies on AC and E lies on AD such that BE is parallel to CD. AB = 21 cm, CD = 18 cm and BE = 13.5 cm. Work out the radius of the circle. cm [5]
Read automatically from the paper; the printed page above is exact.
Show the answer and mark scheme
16.6 or 16.64… [5]
M2 for 18 21× = AC oe [ ] 13.5
or M1 for scale factor 13.5 18 or 18 13.5 oe soi Then Pythagoras method: and
M2 for 28 2 + 18 2 [÷ 2] 2 2 or ( theirAC ) + 18 [÷ 2]
or M1 for 2 2 2 AD = 28 + 18 2 or AD 2 = ( theirAC ) + 18 2 OR alternative trigonometry method e.g.
M1 for tan E = 21 13.5 18 and
M1 for AD = cos their 57.3
Make a free account to save your answers and see your weak topics and ask the AI why a wrong answer is wrong.