Question

find the area of a trapezium whose parallel sides are 11 cm and 25 centimetre long non parallel sides 15 CM 30 cm long respectively

Answer 1

Let AB = 25 cm , CD = 13 cm and BC = CD = AD cm

perpendiculars from C and D to AB meeting AB at F and E are drawn

Therefore, A E = F B = 6 cm

triangle AED,

AD2= AE2+DE2

=AD2AE2+DE2

DE2=AD2−AE2DE2

=AD2−AE2

=102−62=64

=102−62

=64

DE=8cm

Area of the Trapezium = 1/2*h(a+b) sq cm

= 1/2*8(25+13)sq cm =152 sq cm