Q9 of 69 Page 238

Find the area of an isosceles triangle each of whose equal sides measures 13cm and whose base measures 20cm.

Let,


a = 13 cm


b = 13 cm


And,


C = 20 cm


Now,


s =


=


= = 23 cm


We know that,


Area of triangle =


=


=


= 10


= 10 × 8.306


= 83.06 cm2


Therefore,


Area of isosceles triangle = 83.06 cm2


More from this chapter

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7

The perimeter of a triangular field is 540m and its sides are in the ratio 25 : 17 : 12. Find the area of the triangle. Also, find the cost of ploughing the field at Rs. 18.80 per 10m2.

 8

Two sides of a triangular field are 85m and 154m in length and its perimeter is 324m. Find:

(i) The area of the field and


(ii) The length of the perpendicular from the opposite vertex of the side measuring 154m.

 10

The base of an isosceles triangle measures 80cm and its area is 360cm2 . Find the perimeter of the triangle.

 11

The perimeter of an isosceles triangle is 42cm and its base is times, each of the equal sides.

Find:


(i) The length of each side of the triangle


(ii) The area of the triangle


(iii) The height of the triangle.