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Locate 10\sqrt{10} and 17\sqrt{17} on the number line.

Rational Irrational Nos

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Answer

Locating 10\sqrt{10}:

Representing 10 as the sum of squares of two natural numbers:

10 = 9 + 1 = 32 + 12

Let l be the number line. If point O represents number 0 and point A represents number 3, then draw a line segment OA = 3 units.

At A, draw AC ⟂ OA. From AC, cut off AB = 1 unit.

We observe that OAB is a right angled triangle at A. By Pythagoras theorem, we get:

OB2=OA2+AB2OB2=32+12OB2=9+1OB2=10OB=10 unitsOB^2 = OA^2 + AB^2 \\[0.5em] \Rightarrow OB^2 = 3^2 + 1^2 \\[0.5em] \Rightarrow OB^2 = 9 + 1 \\[0.5em] \Rightarrow OB^2 = 10 \\[0.5em] \Rightarrow OB = \sqrt{10} \text{ units} \\[0.5em]

With O as centre and radius = OB, we draw an arc of a circle to meet the number line l at point P.

As OP = OB = 10\sqrt{10} units, the point P will represent the number 10\sqrt{10} on the number line as shown in the figure below:

Locate √10 and √17 on the number line. Rational and Irrational Numbers, ML Aggarwal Understanding Mathematics Solutions ICSE Class 9.

Locating 17\sqrt{17}:

Representing 17 as the sum of squares of two natural numbers:

17 = 16 + 1 = 42 + 12

Let l be the number line. If point O represents number 0 and point A represents number 4, then draw a line segment OA = 4 units.

At A, draw AC ⟂ OA. From AC, cut off AB = 1 unit.

We observe that OAB is a right angled triangle at A. By Pythagoras theorem, we get:

OB2=OA2+AB2OB2=42+12OB2=16+1OB2=17OB=17unitsOB^2 = OA^2 + AB^2 \\[0.5em] \Rightarrow OB^2 = 4^2 + 1^2 \\[0.5em] \Rightarrow OB^2 = 16 + 1 \\[0.5em] \Rightarrow OB^2 = 17 \\[0.5em] \Rightarrow OB = \sqrt{17} \text{units} \\[0.5em]

With O as centre and radius = OB, we draw an arc of a circle to meet the number line l at point P.

As OP = OB = 17\sqrt{17} units, the point P will represent the number 17\sqrt{17} on the number line as shown in the figure below:

Locate √10 and √17 on the number line. Rational and Irrational Numbers, ML Aggarwal Understanding Mathematics Solutions ICSE Class 9.

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