Microsoft Office Tutorials and References

In Depth Information

=ROUND(A1,A2-1-INT(LOG10(ABS(A1))))

For example, if cell A1 contains 1.27845 and cell A2 contains 3, the formula returns
1.28000
(the value, roun-

ded to three significant digits).

Don't confuse this technique with significant decimal digits, which are the number of

digits displayed to the right of the decimal points. It's an entirely different concept.

Also, these formulas make the values less accurate.

Solving Right Triangles

A right triangle has six components: three sides and three angles. Figure 10-3 shows a right triangle with its

various parts labeled. Angles are labeled A, B, and C; sides are labeled Hypotenuse, Base, and Height. Angle C

is always 90 degrees (or PI/2 radians). If you know any two of these components (excluding Angle C, which is

always known), you can use formulas to solve for the others.

Figure 10-3:
A right triangle's components.

The Pythagorean theorem states that

Height^2 + Base^2 = Hypotenuse^2

Therefore, if you know two sides of a right triangle, you can calculate the remaining side. The formula to calcu-

late a right triangle's height (given the length of the hypotenuse and base) is as follows:

=SQRT((hypotenuse^2) - (base^2))

The formula to calculate a right triangle's base (given the length of the hypotenuse and height) is as follows: