Page 136 - NUMINO Challenge_C1

Problem solving

1 In order to make a fan, sticks of various lengths Key Points
are fixed to point O. One end of each stick is
fixed to point O, and the other end moves freely. When the sum of
Find the greatest possible area of the quadrilateral the lengths of the
that can be formed by connecting points A, B, C, two diagonals of a
and D. Remove the paper that is attached to the quadrilateral is fixed,
sticks. the area becomes
greater as the
difference between
the lengths of the
diagonals becomes
smaller.

C

BD

A 6 cm 10 cm

7 cm 9 cm

O

2 There is a dot on the ground. Draw four lines that The grestest area of
start from this dot and connect the other ends of a quadrilateral with
the lines to form a quadrilateral. Find the area of the lengths of the
the greatest patch of ground possible. Note that two diagonals fixed
the sum of the lengths of the four lines is 100 m. is found when the
diagonals meet
perpendicularly.

133Measurement