Question

8.In the figure below, ABCD is a rectangularboard that measures 20 m by 15 m, and
AE = BF = x m. A trapezium CDEF is cut outfrom the rectangular board.
(a) Express EF in terms of x.
(b) If the area of CDEF is 3/4 that of ABCD, find
(i) the area of CDEF,
(ii) the value of x.​

Answer 1

Answer:

i) 225 m square

ii) x= 5 m

Answer 2

Answer:

Step-by-step explanation:

x+EF+x=20

EF=20-2x

ar(CDEF)=3/4 ar( ABCD)

=3/4 *20*15

=3*5*15

=225 cm²

ar (ΔADE)+ar(ΔFBC)=15*20-225=75

So 2*ar(ΔADE)=1/2*120=75

2*1/2*x*15=75

15x=75

x=5 cm