In a quadrilateral ABCD, it is given
that AB is parallel to CD and the
diagonals AC and BD are perpendicular
to each other.
Show that
(a) AD.BC ≥ AB.CD;
(b) AD + BC ≥ AB + CD.
Let ABC be a triangle and h_a the
altitude through A. Prove that
(b + c)^2 ≥ a^2 + 4h_a ^2 .
(As usual a, b, c denote the sides BC,
CA, AB respectively.)
Q. In 2014, country X had 783 miles of paved roads. Starting in
2015, the country has been building 8 miles of new paved
roads each year. At this rate, how many miles of paved roads
will country X have in 2030?
The cyclic octagon ABCDEFGH has
sides a, a, a, a, b, b, b, b respectively.
Find the radius of the circle that
circumscribes ABCDEFGH in terms
of a and b.
Consider the areas of the four triangles
obtained by drawing the diagonals AC
and BD of a trapezium ABCD. The
product of these areas, taken two at
time, are computed. If among the six
products so obtained, two products are
1296 and 576, determine the square
root of the maximum possible area of
the trapezium to the nearest integer.