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Find the perimeter of this semi-circle with diameter, d = 65cm. Give your answer rounded to 1 DP.

1 Answer

6 votes

Answer:

1658.3

Explanation:

the perimeter of a semi - circle is simply half the circumference of a circle.

that is ;

1 / 2 ( pi ( r² ) )

where;

pi = 3.14 ( this is a constant that should be known and also equals 22 / 7 )

r = radius ( or half a diameter )

in our question, we are given a diameter with no radius

this means that we will have to halve the diameter to give us our radius

that is;

d = 65cm

r = 65 / 2

r = 32.5

so, using our formula;

1 / 2 ( 3.14 ( 32.5² ) )

1 / 2 ( 3.14 ( 1056.26 ) )

1 / 2 ( 3316.65 )

1658.3125

rounded to 1 DP;

1658.3

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