Find the third proportional to: (i)$2\frac{2}{3}$ (ii) a – b and a^2 – b^2 - Noon Academy

Find the third proportional to: (i) $2\frac{2}{3}$ (ii) a – b and a^2 – b^2

Class 10 | Exercise 7B | ICSE | Ratio and Proportion | Selina

Find the third proportional to: (i) $2\frac{2}{3}$ (ii) a – b and a^2 – b^2

(i) take the third proportional to
Concise Selina Solutions Class 10 Maths Chapter 7 ex. 7(B) - 2 and 4 be x.

So,
Concise Selina Solutions Class 10 Maths Chapter 7 ex. 7(B) - 3 , 4, x are in continued proportion.

$\begin{array}{*{35}{l}} 8/3:\text{ }4\text{ }=\text{ }4:\text{ }x \\ \left( 8/3 \right)/\text{ }4\text{ }=\text{ }4/x \\ x\text{ }=\text{ }16\text{ *}3/8\text{ }=\text{ }6 \\ \end{array}$

(ii) Let the third proportional to a – b and a² – b² be x.

So, a – b, a² – b², x are in continued proportion.

a – b: a² – b² = a² – b²: x

Concise Selina Solutions Class 10 Maths Chapter 7 ex. 7(B) - 4

i

More Material

A …… lens is used to correct myopia and a ….. lens is used to correct hypermetropia.
A Concave, concave
B Convex, convex
C Convex, concave
D Concave, convex

Rate of reaction of any substance depends on
(A) active mass
(B) molecular weight
(C) atomic weight
(D) equivalent weight

Formula of oleum is
(A) $\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{7}$
(B) $\mathrm{H}_{2} \mathrm{SO}_{4}$
(C) $\mathrm{H}_{2} \mathrm{SO}_{3}$
(D) $\mathrm{H}_{2} \mathrm{SO}_{5}$

A line passes through the point (2, 1, -3) and is parallel to the vector Find the equations of the line in vector and Cartesian forms.

Two cells of emf $\varepsilon_{1}$ and $\varepsilon_{2}$ , internal resistance $r_{1}$ and $r_{2}$ , connected in parallel. The equivalent emf of the combination is- (A) $\frac{\varepsilon_{1} r_{1}+\varepsilon_{1} r_{1}}{r_{1}+r_{2}}$ (B) $\frac{\varepsilon_{1} r_{2}+\varepsilon_{2} r_{1}}{r_{1}+r_{2}}$ (C) $\sqrt{\varepsilon_{1} \times \varepsilon_{2}}$ (D) $\frac{\varepsilon_{1}+\varepsilon_{2}}{2}$

If the points $A(a, 0), B(0, b)$ and $C(1,1)$ are collinear, prove that $\frac{1}{a}+\frac{1}{b}=1$

If $A(-2,0), B(0,4)$ and $C(0, k)$ be three points such that area of a $A B C$ is 4 sq units, find the value of $k$ .

Find the value of $k$ for which the area of a ABC having vertices $A(2,-6), B(5,4)$ and $C(k, 4)$ is 35 sq units.

Find the value of $k$ for which the points $A(1,-1), B(2, k)$ and $C(4,5)$ are collinear.

Find the value of $k$ for which the points $P(5,5), Q(k, 1)$ and $R(11,7)$ are collinear.

Find the value of $k$ for which the points $A(3,-2), B(k, 2)$ and $C(8,8)$ are collinear.

Use determinants to show that the following points are collinear. $P(-2,5), Q(-6,-7)$ and $R(-5,-4)$

← Previous Next →