1: Find the value of x if the ratios 5:6 and x: 15.6 are:(i) directly

1.	1: Find the value of x if the ratios 5:6 and x: 15.6 are:(i) directly proportional(ii) inversely proportional
Answer» (I) If the ratios are directly proportional, then 5 : 6 = X : 15.6 $= > \frac{5}{6} = \frac{x}{15.6}$ $= > x = \frac{5 \times 15.6}{6} = 13$ (II) If the ratios are INVERSELY proportional, then 5 : 6 = inverse of x : 15.6 = 15.6 : x $= > \frac{5}{6} = \frac{15.6}{x}$ $= > x = \frac{15.6 \times 6}{5} = 18.72$ Points to Remember: =================== If a:b is directly proportional to C:d, then a:b = c:d or ad = bc. (by CROSS multiplication) If a:b is inversely proportional to c:d, then a:b = inverse of c:d = d:c or ac = bd. (by cross multiplication)

1: Find the value of x if the ratios 5:6 and x: 15.6 are:(i) directly proportional(ii) inversely proportional

Answer»

(I) If the ratios are directly proportional, then

5 : 6 = X : 15.6

$= > \frac{5}{6} = \frac{x}{15.6}$

$= > x = \frac{5 \times 15.6}{6} = 13$

(II) If the ratios are INVERSELY proportional, then

5 : 6 = inverse of x : 15.6 = 15.6 : x

$= > \frac{5}{6} = \frac{15.6}{x}$

$= > x = \frac{15.6 \times 6}{5} = 18.72$

Points to Remember:

===================

If a:b is directly proportional to C:d, then a:b = c:d or ad = bc. (by CROSS multiplication)

If a:b is inversely proportional to c:d, then a:b = inverse of c:d = d:c or ac = bd. (by cross multiplication)