78.5= (3.14)r^2
25=r^2
5=r
So, the radius of a circle with an area is 78.5 cm^2 is 5 cm^2

As we know ~
Area of the circle is :

And radius (r) = diameter (d) ÷ 2
[ radius of the circle = half the measure of diameter ]
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<h3>Problem 1</h3>



Now find the Area ~




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<h3>problem 2</h3>



Bow, calculate the Area ~




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<h3>Problem 3 </h3>




・ .━━━━━━━†━━━━━━━━━.・
<h3>Problem 4</h3>



now, let's calculate area ~



・ .━━━━━━━†━━━━━━━━━.・
<h3>problem 5</h3>



Now, let's calculate area ~




・ .━━━━━━━†━━━━━━━━━.・
<h3>problem 6</h3>




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It's scientific notation, so 1.4x10^7 would be 14000000 <span />