15. Triangles ABC and DEF are similar.
Work out the length of BC.
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10cm

Step-by-step explanation:

Since ABC and DEF are similar, the ratio of their side is always the same.

The ratio here is:

DF/AC = 6/4 = 1.5

Therefore, it means that BC x 1.5 = EF

So:

BC x 1.5 = 15

BC = 15 / 1.5 = 10cm.

52 degrees

Step-by-step explanation:

both degrees have to equal 9 because it is a right angle. so subtract 90 and 38 to get your answer.