Question

Is that not right? or am I just wrong cause it says that it is not right please help

Answer 1

Answer:

98 cm²

Step-by-step explanation:

The area of a circle is:

$A=\pi r^2$

A semicircle is half a circle therefore the area of a semicircle would be:

$A=\frac{1}{2}\pi r^2$

We can plug in the given values into the equation:

$A=\frac{1}{2}*3.142*(7.9)^2\\A=\frac{1}{2}*3.142*62.41\\A=\frac{1}{2}*196.09222 \\A=98.04611$

We need to round to TWO sigfigs meaning...

$A=98 \ cm^2$

Sigfig rules:

Nonzero numbers are significant

Trailing zeros are significant (only if there is a decimal point)

Any sandwiched zero is signification (Ex: 405 --> 3 sigfigs)