In un triangolo la somma e la differenza fra la base e l'altezza misurano rispet tivamente 63 cm e 7 cm . Calcola l'area. [490 \( \left.\mathrm{cm}^{2}\right] \)

काम का पृष्ठीय क्षेत्रफल 1300 सेमी \( ^{2} \) है। यदि इसकी चौड़ाई 10 सें को 20 सेमी है तो इसकी लम्बाई ज्ञात कीजिए।

(घ) सिद्ध कीजिए के त्रिभुज कै तीनों अन्त: कोणों का योग \( 180^{\circ} \) होता है

24) ABC is a triangle in which \( \mathrm{m}(\angle \mathrm{A})=60^{\circ}, \mathrm{b}: \mathrm{c}=5: 8 \) and the area of the circumcircle of the triangle ABC is \( 147 \pi \mathrm{~cm}^{2} \), then the perimeter of \( \triangle \mathrm{ABC}=\ldots \ldots \ldots \cdots \cdot \mathrm{cm} \). \( \begin{array}{llll}\text { (a) } 21 & \text { (b) } 34 & \text { (c) } 54 & \text { (d) } 60\end{array} \)

Find the condition at which the line \( l x+m y+n=0 \) touches the circle \( x^{2}+y^{2}+28 x+2 f y+c=0 \) For what value of \( n \), a. the line \( 3 x+4 y+n=0 \) touches the circle \( x^{2}+y^{2}-4 x-6 y-12-02 \)

A triangle has a perimeter of 20 and two of its sides measure 7 and 5 . What is the length of the third side?