Question

at a particular time of a day a 7 M high flagstaff Casts a shadow which is 8.2 M long what is the height of the building which Casts a shadow 20.5 m in length at the same moment

Answer 1

the height of the object is directly proportional to the height of the shadow. So,

x2/x1 = y2/y1
x2 = y2/y1 × x1
=20.5/8.2×7
=143.5/8.2
=17.5 m

so the answer is 17.5 m. I hope this helps you