Mathematics
Using only ruler and compass, construct an angle of 90°. Then construct an angle of 45° by bisecting it.
Answer
Steps of construction :
Draw a line l. Mark two points O and A on the line l.
With O as centre and a convenient radius, draw an arc cutting OA at P.
With P as centre and the same radius, cut the arc at Q. With Q as centre and the same radius, cut the arc again at R.
With Q and R as centres and radius more than half of QR, draw two arcs intersecting at S. Join OS. Then ∠AOS = 90°.
To get 45°, bisect ∠AOS : with P and the point M, as centres, draw two arcs intersecting at T. Join OT. Then ∠AOT = 45°.

Hence, ∠AOS = 90° and on bisecting it, ∠AOT = 45° is constructed.
Related Questions
Subtract 62.75 from the sum of 48.92 and 76.58. Also round off the answer to the nearest tenth.
Amit is designing a logo using geometric shapes. He draws:
(a) A closed curve with 4 straight sides
(b) A straight line that extends infinitely in both directions
(c) A shape that has a centre and all points on the boundary are at the same distance from it.
Answer the following questions:
(a) What is the name of the closed curve with 4 sides?
(b) What is the name of the second shape Amit drew?
(c) What is the third shape? What is the name of the line segment joining the centre to any point on the boundary?
Study the following floor plan of a house prepared by an architect.

Some of the measurements are given.
(i) Find the missing measurements.
(ii) Find out the total area of the house (including the Garden).