Prove that an angle inscribed in a semi-circle is a right angle.

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsShort Answer Type

Advertisement

221.
Prove that an angle inscribed in a semi-circle is a right angle.


Let O be the centre of the semi circle and AB be the diameter. Let P be any point on the circumference of the semi circle.
Let OA with rightwards arrow on top space equals space straight a with rightwards arrow on top comma space space then space OB with rightwards arrow on top space equals negative straight a with rightwards arrow on top.
Let OP with rightwards arrow on top space equals space straight r with rightwards arrow on top
therefore space space space AP with rightwards arrow on top space equals OP with rightwards arrow on top space minus space OA with rightwards arrow on top space equals space straight r with rightwards arrow on top space minus space straight a with rightwards arrow on top
space space space space space space space BP with rightwards arrow on top space equals space OP with rightwards arrow on top space minus space OB with rightwards arrow on top space equals straight r with rightwards arrow on top space minus space left parenthesis straight a with rightwards arrow on top right parenthesis space equals space straight r with rightwards arrow on top plus straight a with rightwards arrow on top
AP with rightwards arrow on top space BP with rightwards arrow on top space equals space left parenthesis straight r with rightwards arrow on top space minus space straight a with rightwards arrow on top right parenthesis. space left parenthesis straight r with rightwards arrow on top space plus space straight a with rightwards arrow on top right parenthesis space equals space straight r with rightwards arrow on top squared space minus space straight a with rightwards arrow on top squared
space space space space space space space space space space space space space equals straight a squared minus straight a squared space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space open square brackets because straight r space equals space straight a space as space OP space equals space OA close square brackets
therefore space space space AP with rightwards arrow on top space space is space perpendicular space to space BP with rightwards arrow on top
rightwards double arrow space space angle APB space space equals space 90 degree
Hence space the space result. space space space space space space space space


87 Views

Advertisement

 Multiple Choice QuestionsLong Answer Type

222. Using vectors, prove that if two medians of a triangle ABC be equal, then it is an isosceles triangle. 
157 Views

223. Using vectors, prove that the perpendicular bisectors of the sides of a triangle are concurrent.
274 Views

 Multiple Choice QuestionsShort Answer Type

224. Prove that the median to the base of isosceles triangle is perpendicular to the base.
257 Views

Advertisement

 Multiple Choice QuestionsLong Answer Type

225. If the median of the base of a triangle is perpendicular on the base, then prove that the triangle is an isosceles.
90 Views

226. (i) Prove that cos (α + β) )= cos α cos β – sin α sin β.
(ii)  Prove that cos (α – p) = cos α cos β + sin α sin β.
85 Views

227. Prove that the diagonals of a rectangle are perpendicular if and only if the rectangle is a square.
87 Views

 Multiple Choice QuestionsShort Answer Type

228. Using vectors, prove that a parallelogram whose diagonals are equal is a rectangle. 
88 Views

Advertisement

 Multiple Choice QuestionsLong Answer Type

229. Prove using vectors: The quadrilateral obtained by joining mid-points of adjacent sides of a rectangle is a rhombus.
78 Views

230. Show that the angle between two diagonals of a cube is cos to the power of negative 1 end exponent space open parentheses 1 third close parentheses.
82 Views

Advertisement