Seven equal cubes each of side $5 \, cm$ are joined end to end. Find the surface area of the resulting cuboid? (in $cm^2$)

If the length and breadth of a rectangular plot are increased by $50 \%$ and $20 \%$ respectively,then how many times will its area be increased?

If $D, E$ and $F$ are the mid-points of the sides of an equilateral triangle $ABC,$ then the ratio of the area of triangle $DEF$ and $DCF$ is

The ratio of the area of a square to that of the square drawn on its diagonal is

The ratio of bases of two triangles is $x: y$ and that of their areas is $a: b$. Then the ratio of their corresponding altitudes will be

The angles of a quadrilateral are in the ratio of $2: 4: 7: 5$. The smallest angle of the quadrilateral is equal to the smallest angle of a triangle. One of the angles of the triangle is twice the smallest angle of the triangle. What is the second largest angle of the triangle? (in $^o$)