What is the highest common factor of 75 and 90?

75 = 3 x 25
75 = 3 x 5 x 5

90 = 3 x 30
90 = 3 x 3 x 10
90 = 2 x 3 x 3 x 5

H.C.F = 3 x 5 = 15

75: x, 3, x, 5, 5
90: 2, 3, 3, 5, x
xx: x, 3, x, 5, x
= 15

Answer: 15

prime factors of 75 = 3, 5
prime factors of 90 = 2, 3, 5

the common factors are 5 and 3

multiply the common factors

3x5=15

f i f t e e n

75 = 3 x 5 x 5
90 = 2 x 3 x 3 x 5
-----------------------
The HCF of 75,90 is:
3 x 5
= 15

15

Fifteen!

15.

Method:
Prime factor both numbers:
90: 2*3*3*5
75: 3*5*5
Factors the numbers share:3*5=15.

15.