Pawan Prajapati
Last Activity: 3 Years ago
Hint: Use the fact that if two sides of a right-angled triangle are x−−√ and 1, then the hypotenuse is given by x+1−−−−−√. Hence form a right-angled triangle with sides, 1 and 1. The hypotenuse will be 2–√. Then using the length of hypotenuse form another right-angled triangle with sides, 3–√ and 1. The hypotenuse of that triangle will be 3–√. Continue in the same way till we get the hypotenuse length as 7–√. Now extend compass length to be equal to 7–√ (Keep one arm of the compass on one endpoint of the hypotenuse and the other arm on the other endpoint of the hypotenuse). Draw an arc with 0 as the centre and let it intersect the positive x-axis at some point. The point then represents 7–√ on the number line.
Complete step-by-step answer:
Consider a right-angled triangle with side length as 1,1 as shown below
Hence BC=12+12−−−−−−√=2–√
Draw CD perpendicular BC and CD = 1 unit as shown below.
Hence BD=(2–√)2+12−−−−−−−−−√=3–√
Draw CE perpendicular to BD, CE = 1 unit.
Hence BE=(3–√)2+1−−−−−−−−√=4–√
Draw EF perpendicular to BE, EF = 1 unit as shown below
Hence BF=(4–√)2+1−−−−−−−−√=5–√
Draw FG perpendicular BF and FG = 1 unit as shown below.
Hence BG=(5–√)2+1−−−−−−−−√=6–√
Draw GH perpendicular BG and GH = 1 unit, as shown below.
Hence BH=(6–√)2+1−−−−−−−−√=7–√
With O as centre and radius BH, mark draw an arc and let it intersect the positive x-axis at M. M represents 7–√ on the number line.
Hence 7–√ is represented on the number line.
Note: Alternative method: Best Method:
Draw OX = 7 units.
Extend OX to P such that XP = 1 unit.
Now locate the midpoint of OP by drawing perpendicular bisector of OP. Let it intersect OP at A as shown below.
With A as centre and radius OP draw a semicircle as shown below
Now draw a line parallel to the perpendicular bisector through X and let it intersect the semicircle at B as shown below.
Hence XB=7–√
Now extend compass to be of radius XB draw an arc from O and let it intersect OP at C.
C represents 7–√ on the number line.