Find the area of a kite ABCD if BD= 48cm, AB= 25cm, and BC= 26cm?

1 Answer
Jan 4, 2016

S=408cm2

Explanation:

The formula of a kite's area is
S=(12)d1d2
where
d1=kite's long diagonal
d2=kite's short diagonal

In the problem, be noticed that once the diagonal BD has an endpoint in B (where 2 segments of different sizes, AB and BD, meet), this diagonal is divided in two equal parts by the other diagonal. Calling E the point where the two diagonals intercept each other, we have:
BD=2DE=48 => DE=24

In the right triangle ABE we can obtain the segment AE
AB2=DE2+AE2 => 252=242+AE2 => AE=625576=49=7

In the right triangle BCE we can obtain the segment CE
BC2=DE2+CE2 => 262=242+CE2 => CE=676576=100=10

In this way we discovered the previously unknown diagonal:
AC=AE+CE=7+10=17

Finally,
S=(12)(d1+d2)=48+172=408cm2