In ΔABC, D and E are points on side AB and AC respectively. DE is parallel to BC. If lengths of AD, DB and AE are 8 cm, 4 cm and 12 cm respectively, what is the length of AC?
In a trapezium ABCD, AB and DC are parallel sides and ∠ ADC = 90°. If AB = 15 cm, CD = 40 cm and diagonal AC = 41 cm. Then the area of the trapezium ABCD is