Question
Find the fourth proportional to $3a, 6a^2$ and $2ab^2$
✓
Answer
Let the fourth proportional to $3a, 6a^2$ and $2ab^2$ be $x.$
$\Rightarrow 3a : 6a^2 = 2ab^2 : x$
$\Rightarrow 3a \times x = 2ab^2 6a^2$
$\Rightarrow 3a \times x = 12a^3b^2$
$\Rightarrow x = 4a^2b^2$
$\Rightarrow 3a : 6a^2 = 2ab^2 : x$
$\Rightarrow 3a \times x = 2ab^2 6a^2$
$\Rightarrow 3a \times x = 12a^3b^2$
$\Rightarrow x = 4a^2b^2$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
From a well shuffled deck of 52 cards, one card is drawn. Find the probability that the card drawn is:
a card with number 5 or 6
a card with number 5 or 6
Part of geometrical figure is given in each of the diagrams below. Complete the figures, so that the line ‘m’, in each case, is the line of symmetry, of the completed figure. Recognizable free hand sketches, would be awarded full marks.
AB is a diameter of the circle APBR as shown in the figure. APQ and RBQ are straight lines. Find : ∠ PBR
Prove that $cosec^2 (90^\circ - \theta ) + \cot^2 (90^\circ - \theta ) = 1 + 2 \tan^2 \theta .$
→A bag contains twenty Rs 5 coins, fifty Rs 2 coins and thirty Re 1 coins. If it is equally likely that one of the coins will fall down when the bag is turned upside down, what is the probability that the coin:
will neither be a Rs 5 coin nor be a Re 1 coin?
will neither be a Rs 5 coin nor be a Re 1 coin?
Prove that : $1-\frac{\cos ^2 \theta}{1+\sin \theta}=\sin \theta$
→A card is drawn from a pack of well-shuffled 52 playing cards. Find the probability that the card is drawn is a face card.
Represent the solution of the given inequalities on the real number line
$\frac{2 x+5}{3}>3 x-3$
→$\frac{2 x+5}{3}>3 x-3$
AB is a diameter of a circle with centre C = (- 2, 5). If A = (3, – 7). Find
(i) the length of radius AC
(ii) the coordinates of B.
(i) the length of radius AC
(ii) the coordinates of B.
Find the value of x, if $\cos x=\cos 60^{\circ} \cos 30^{\circ}-\sin 60^{\circ} \sin 30^{\circ}$
→