In this section you will learn constructing angles.
"Construction" in Geometry means to draw shapes, angles or lines accurately.
In constructing-angles, mostly we use compass and ruler.
Construction of Angles equal to a given angle
Draw an angle of measure 700
. Make a copy of it using ruler and compasses.
Step 1: With the help of a protractor, draw an angle ∠DAP of measure 700
Step 2: Draw a line l and a point P on it.
Step 3: Place the compasses at A and draw an arc to cut the rays of ∠A at B and C.
Step 4: Use the same compasses setting to draw an arc with P as center, cutting l in Q.
Step 5: Set your compasses to the length BC with the same radius.
Step 6: Place the compasses pointer at Q and draw the arc to cut the arc drawn earlier in R.
Step 7: Join PR. This gives ∠P. It has the same as ∠DAP.
∴ ∠DAP = ∠RPQ.
Example 2 :
Draw an angle of 600
using compass and then draw a copy of angle 60.
Steps of constructing angles :
Step 1 :Draw a ray PC.
Step 2 : Place the pointer of the compasses at P and draw an arc of convenient radius which cuts the ray PC at a point A.
Step 3 : With the pointer at A (as centre) and with same radius now draw an arc that cuts the previous one at point B.
Step 4 : Join PB. We obtain ∠BPA whose measure is 600
step 5 : Now draw another ray XY
Step 6 : Place the pointer of the compasses at X and draw an arc of convenient radius which cuts the ray XY at a point M.
Step 7 : With the pointer at M (as centre) and with same radius now draw an arc that cuts the previous one at point N.
Step 8 : Join XN. We obtain ∠NXM whose measure is equal to ∠BPA = 600
1) Given angle is 350
. Construct an angle which equal to 350
2) for obtaining angle 1050
, which two angles you will bisect.
• Basic Geometric Constructions
• Construction of Line Segment
• Bisecting a Line Segment
• Constructing Angles
• Bisecting Angles
• Constructing Parallel Lines
• Construction of Triangle (SSS)
• SAS Triangle Construction
• ASA Triangle Construction
• HL Triangle Construction (Rhs -construction)
• Constructing Quadrilaterals
• Constructing Triangles(when sum of sides or perimeter is given)