Three small lead spheres of radius 3 cm, 4 cm and 5 cm respectively, are melted into a single sphere. The diameter of the new sphere is

If the length of each median of an equilateral triangle is $6 \sqrt{3}$ cm, the perimeter of the triangle is

Two cubes of sides 6 cm each are kept side by side to form a rectangular parallelopiped. The area (in sq. cm) of the whole surface of the rectangular parallelopiped is

What is the value of $\frac{(1.1)^{3}+(0.7)^{3}}{(1.1)^{2}-1.1 \times 0.7+(0.7)^{2}} ?$

If tan 7θ tan 2θ = 1, then the value of tan 3θ is

$\mathrm{AB}$ and $\mathrm{CD}$ are two parallel chords on the opposite sides of the centre of the circle. If $\overline{\mathrm{AB}}=10 \mathrm{~cm}$, $\overline{\mathrm{CD}}=24 \mathrm{~cm}$ and the radius of the circle is $13 \mathrm{~cm}$, the distance between the chords is

What will be the radius of circle in which a central angle of 60° intercepts an arc of length 37.4 cm.

A chord of a circle is equal to its radius. The angle subtended by this chord at a point on the circumference in the major segment is

If $x^{2}-3 x+1=0$, what is the value of $\left(x^{4}-\frac{1}{x^{4}}\right) ?$