Experts can you please solve question no. 10

Experts can you please solve question no. 10 1. The parallel sides of a 3_9cm ; and the other sides Find 8. The following figure shows that cross section of a concrete structure with the measur as given. Calculate the area of the cross-section. 9. (n the figure find: (ii) area of the trapezium ABC'D_ 10. The cross-section of a tunnel perpendicular to its length is a trapezium ABC'D as showd of paving the rate of A With its the measure 98 cm and 12 The oi the lengths Of the parallel sides of the trapezium. when its rectangle. 12. ute ctss-rctüM of a canal is in Ibe shape Of a tratwzium, If the canal is 12 m •Alde topand 8 m w ide at the bottom and area section is 84 m: , ANSWERS

The cross section of a tunnel  is of trapezium shaped  ABCD in which AB=4.4 m, CD=3 m and AM=BN.The height is 2.4 m and its length is 50m(i) AM=BN=4.4-32=1.42=0.7 mIn ADMAD2=AM2+DM2   using pythagoras theorem=0.72+2.42=0.49+5.76=6.25 mSo, AD=2.5 mPerimeter of the cross section of the tunnel =AB+AD+BC+CD=4.4+2.5+2.5+3  as AD=BC=12.4 mLength=50 mSo, internal surface area of the tunnel except floor=12.4×50-50×4.4=620-220 m2=400 m2rate of painting =Rs 5/m2hence the total cost of painting =Rs 5×400=Rs 2000(ii) Area of floor of tunnel  =l×b  where l=length ,b=breadth=50×4.4=220 m2Rate of cost of paving =Rs 18/m2Total cost=220×18=Rs 3960

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