Question

Find the third proportional to rupees 4 and 12 and for 1km 500m to 300m

Answer 1

(1) let , a = 4 , b = 12 and c is the required third proportional

a : b = b : c

4 : 12 = 12 : c

4 / 12 = 12 / c

4 c = 12 × 12

c = 144 / 4 = 36

therefore ,

third proportional = 36

4 c = 144

(2) : Find third proportional of 1km 500m, 300 m

let a = 1 km 500m = 1000m + 500m = 1500 m

and b = 300 m

a : b = b : c

1500 : 300 = 300 : c

1500 / 300 = 300 / c

1500 × c = 300 × 300

1500 c = 90000

c = 60

therefore therefore proportional = 60

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Your Answer : ( 1) = 36 , (2) = 60
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Answer 2

a)

=> a = 4

=> b = 12

=> c be the third proportional

condition :-

a : b = b : c

4 : 12 = 12 : c

4c = 12 × 12

4c = 144

c = 144/4

c =36

b)

=> a = 1km 500m

1km = 1000m

so a = 1000 + 500 =1500

=> b = 300m

=> c be the third proportional

condition :-

a : b = b : c

1500 : 300 = 300 ; c

1500c = 300 × 300

1500c = 90000

c = 90000/1500

c = 60