Question

The baseof an isosceles triangle measure 80cm and its area 360cm. Find the perimeter of the triangle

Answer 1

The base of an isosceles triangle=b=80cm .Area of the triangle =360 sq.cm. =1/2bh=> 360 =1/2(80)h=>
360/40 =9 cm = h .So the height of the triangle =9cm. So perimeter of the isosceles triangle=80+9+9=98cm Or perimeter of the isosceles triangle=80+80+9=169 cm .

Answer 2

Hi pupil here's your answer ::

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⏩Height = ?
⏩Base = 80 cm

☝area of an isosceles triangle =》1/2 b×h

✔ 360 cm = 1/2 80×h
✔ 360 = 40 ×h
✔ 360/40=h
✔ h=9 cm

✌The perimeter of an isosceles triangle
=》
${b} + \sqrt{ {b}^{2} + {4h}^{2} }$

=》
${80} + \sqrt{ {80}^{2} \: + 4 \times {9}^{2} }$
=》80 + root 160+4×81 (cancel off root with making the square ){80×80} {2×2} {9×9}
=》80+80+9
=》169cm ans

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hope that it helps. . . . . . .