Lúcia is using energy at a rate of 420 kilocalories (kcal) per hour (h) ice skating.

7000 cal/min

Step-by-step explanation:

It is mentioned that, Lucia is using energy at a rate of 420 kilo calories per hour ice skating

We know that,

1 kilo calories = 1000 calories

Using unitary method :

420 kilo calories = 420,000 calories

Also,

1 hour = 60 minutes

In this case, Lucia is using energy per 60 minutes =  420,000 calories. So,energy used by her per minute is :

Hence, Lucia is using 7000 calories per minute.

Credit to handgunmaine:

< coa = 150 ( given)

as ba and bc are tangents

so oc and oa is perpendicular to cb and ab respectively because in circle normal passes through centre

so in quadrilateral oabc

< coa + < oab + < ocb + < abc = 360

150 +90+90 + < abc = 360

330 + < abc = 360

< abc = 360 -330 = 30

so < abc = 30

⭐dhruv⭐

answer: 177/8

step-by-step explanation: