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Question
Show the number √7 on the number line.
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Solution
Draw a number line as shown in the figure and mark the points O, A and B on it such that OA = AB = 1 unit. The point O represents 0 and B represents 2. At B, draw CB perpendicular on the number line such that BC = 1 unit. Join OC. Now, ∆OBC is a right angled triangle.
In ∆OBC, by Pythagoras theorem
(OC)2 = (OB)2 + (BC)2
= (2)2 + (1)2
= 4 + 1
= 5
∴ OC = √5
Taking O as centre and radius OC = √5 , draw an arc cutting the number line at D.
Clearly, OC = OD = √5
At D, draw ED perpendicular on the number line such that ED = 1 unit. Join OE. Now, ∆ODE is a right angled triangle.
In ∆ODE, by Pythagoras theorem
(OE)2 = (OD)2 + (DE)2
= (√5)2 + (1)2
= 5 + 1
= 6
∴ OE = √6
Taking O as centre and radius OE = √6 , draw an arc cutting the number line at F.
Clearly, OE = OF = √6
At F, draw GF perpendicular on the number line such that GF = 1 unit. Join OG. Now, ∆OFG is a right angled triangle.
In ∆OFG, by Pythagoras theorem
(OG)2 = (OF)2 + (FG)2
= (√6)2 + (1)2
= 6 + 1
= 7
∴ OG = √7
Taking O as centre and radius OG = √7 , draw an arc cutting the number line at H.
Clearly, OG = OH = √7
Hence, H represents √7 on the number line.
RELATED QUESTIONS
Write five rational numbers which are smaller than 2.
Show the following numbers on a number line. Draw a separate number line for the example.
`7/5 , (-2)/5 , (-4)/5`
The number `sqrt2` is shown on a number line. Steps are given to show `sqrt3` on the number line using `sqrt2`. Fill in the boxes properly and complete the activity.
Activity :
- The point Q on the number line shows the number ______.
- A line perpendicular to the number line is drawn through the point Q. Point R is at unit distance from Q on the line.
- Right angled ∆ORQ is obtained by drawing seg OR.
`l ("OQ") = sqrt2` , `l("QR") = 1`
`therefore` by Pythagoras theorem,
`[l("OR")]^2 = [l("OQ")]^2 + [l("QR")]^2 `
= `square^2`+ `square^2` = `square` + `square`
= `square`
∴ l(OR) = `square`
Draw an arc with centre O and radius OR. Mark the point of intersection of the line and the arc as C. The point C shows the number `sqrt3`.
Show the number √5 on the number line.
Draw a number line and represent the following rational numbers on it
`(-17)/(-5)`
The rational number `57/23` lies to the left of zero on the number line.
The rational numbers can be represented on the number line.
On a number line, `4/3` is to the ______ of zero (0).
The rational number `(-3)/4` lies to the right of zero on the number line.
Find a rational number exactly halfway between:
`(-1)/3` and `1/3`
