3. Find a vector perpendicular to the plane of using the points \( P=(1,2,-4) \), \( Q=(2,5,-7) \) and \( R=(3,-5,-1) \). Also find area of the parallelogram and area of triangle. Furthermore find a unit vector perpendicular to the plane using these points.

2. In a circle with centre \( O \) and radius \( 13 \mathrm{~cm}, \mathrm{AB} \) is a chord. If \( \mathrm{OM} \perp \mathrm{AB} \) and \( O M=5 \) is the length of \( A B \) ? 3. In a circle of radius 7 cm , find the distance of a chord of length 9 cm from the cent 4. In circle of radius 13 cm , a chord is drawn at a distance 12 cm from the centre. length of the chord. 5. A chord of a circle is 6 cm in length and its distance from the centre is 4 cm . Find th of the same circle.

wer the following questions: hoose the correct answer from the given ones : If the lengths of two sides of a triangle are 2 cm . and 5 cm ., then the perimeter of the triangle \( \in \)...........

Analitik düzlemde \( d_{1}: 2 x+y-12=0 \) ve \( d_{2}: x-y+6=0 \) doğruları veriliyor. 9. \( d_{1} \) ve \( d_{2} \) doğruları ile \( x \) ekseni arasında kalan alanın kaç birimkare olduğunu bulu- nuz. 10. \( d_{1} \) ve \( d_{2} \) doğruları ile eksenler arasında kalan alanın kaç birimkare olduğunu bulunuz.

Identify the measure of each interior angle of a regular 15 - gon.

If the radius of a sphere is doubled, how does the surface area change compared to the original surface area?