Question

To find the polluted region in different areas of Dwarka (a part of Delhi represented by the circle given below) a survey was conducted by the students of class X. It was found that the shaded region is the polluted region, where O is the centre of the circle. Colony A Colony B Colony Colony D​

Answer 1

This is the given figure for your question

We can clearly see that in the big triangle, the base is the diameter, ie CB

And also the diameter CB divides the circle into two equal halves, i.e 2 semi circles.

Now using the identity we studied in class 9: Angles subtended in a semi circle is 90 degree, we can conclude that Angle CAB is 90 degree.

Angle opposite to 90 degree is the hypotenuse. So CB here is the hypotenuse.

We can apply pythagoras theorem: 24^2 + 7^2 = CB^2

=>  576 + 49 = $\sqrt{625$

=> 25

Now we found the diameter is 25 cm, Radius = 12.5 cm

You can find the rest by just simple area formula and stuff

Answer 2

Answer:

a = b ,

b =c ,

c=d,

d=e,

e=a

Step-by-step explanation:

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