Question

please answer these question ​

Answer 1

Answer:

d) surface area of cube = 486 cm^2

6a^2=486

a^2 =486/6

a^2= 81

a=9 cm

length of diagonal= root 3 ×a

1.732× 9 =15.588 cm

volume of cube= a^3

= 9^3= 729 cm^3

e) given p^2+q^2= 67 and pq=9

(p+q)^2= p^2+q^2+2pq

=67+ 18

(p+q)^2 = 85 = p+q = root of 85 = 9.21

therefore p+q= 9.21_____(1)

now,( p-q)^2=p^2+q^2-2pq

= 67-18

(p-q)^2 =49

p-q=7

now multiply by p+q on both sides

(p-q)(p+q)= 7 ( p+q)

p^2-q^2= 7× 9.21 from (1)

p^2-q^2 = 64.47