Question

15. In the drawing, find the perimeter of triangle BIS.
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Answer 1

29.86 units

Explanation:

In the triangle BIS, IT is the bisector of angle BIS,

`BI \cong ST.... (given) \\`

Let BI = ST = x... (1)

By angle bisector property of a triangle, we have:

`(BI)/(IS) = (BT)/(ST).... (2)\\\\</p><p>(x)/(12) = (4)/(x)\\\\</p><p>x* x = 12* 4\\\\</p><p>x^2 = 48\\\\</p><p>x=√(48)\\\\</p><p>x = 6.92820323\\\\</p><p>x = 6.93\\`

Therefore,

BI = ST =6.93

Perimeter of triangle BIS

= BI + IS + ST + BT

= 6.93 + 12 + 6.93 + 4

= 29.86 units