\(\triangle BDC\) is an equilateral triangle with side a = 26 cm.
By using Pythagoras theorem in the right – angled triangle \(\triangle DAB,\) we get:
Area of the quadrilateral
= Area of \(\triangle BCD\) + Area of \(\triangle ABD\)
= 292.37 + 120
= 412.37 cm2
Perimeter of the quadrilateral
= AB + AC + CD + AD
= 24 + 10 + 26 + 26
= 86 cm